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0ИССЛЕДОВАНИЕ СВОЙСТВ ВЕЩЕСТВ И ПРОДУКЦИИ АПК
YflK 663.813
Evaluation of Antioxidant Properties of Commercial Pomegranate Juices
Peter the Great St.Petersburg Polytechnic University
LiudmiLa P. NiLova, SvetLana M. MaLyutenkova, PoLina S. Lebedeva
CORRESPONDENCE: Liudmila P. Nilova
Adress: 195251, Russia, St.Petersburg, Polytechnicheskaya, 29 E-mail: nilova_l_p@mail.ru
FOR CITATIONS:
Nilova, L.P., Malyutenkova, S.M., & Lebedeva, P.S. (2023). The Role of Biologically Active Substances in the Formation of Antioxidant Properties of Pomegranate Juice. Storage and Processing of Farm Products, (1), 83-96. https://doi.org/10.36107/spfp.2023.401
RECEIVED: 23.01.2023 ACCEPTED: 06.03.2023 PUBLISHED: 30.03.2023
DECLARATION OF COMPETING INTEREST: none declared.
ABSTRACT
Background. Consumers consider pomegranate juice one of the most beneficial for health. The limited production of pomegranates in Russia cannot meet the needs of Russian consumers with juices of its own production. Pomegranate juices are produced from concentrates or pasteurized direct-squeezed juices imported from different countries, there is no information about their antioxidant properties.
Purpose. Study of the content of the main biologically active substances and antioxidant activity of pomegranate juice of various brands on the consumer market, and their influence on the formation of antioxidant properties.
Materials and Methods. The objects of research were freshly pressed juice from pomegranate fruits (control)and samples of commercial pomegranate juices produced using different technologies: "Grande", "Benature", "Grante" - direct-squeezed juice; "Swell", "O'keM", "Rich", "Gold Brand" - reconstituted pomegranate juice; "Nar" - reconstituted juice with the addition of direct-squeezed juice. In juices, the total content of phenolic compounds, anthocyanin, flavonoids, tannins and vitamin C was determined. The antioxidant activity of juices was determined by two methods: FRAP and coulometrictitration based on the measurement results of which the antioxidant index was calculated.
Results. Juices of industrial production differed significantly in the amount of biologically active substances, the spread of values in their content between juices was 40-50 %, they contained significantly less total anthocyanin and total flavonoids than freshly-pressed juice. Total tannins prevailed in the composition of phenolic compounds of all juices (40-75 %). The antioxidant activity of juices varied depending on the method of determination. The FRAP test showed the highest values of antioxidant activity in the reconstituted pomegranate juice "Rich", and the coulometric titration showed the highest values in the direct-squeezed pomegranate juice "Benature". Juices had the highest antioxidant index Rich>Benature>Grante, the values of which were more than 85 %. The antioxidant properties of pomegranate juices depend on the total amount of phenolic compounds (R 2 > 0.772) and total tannins (R 2 > 0.538).
Conclusions. The formation of antioxidant properties of pomegranate juices depends on the amount of total phenolic compounds and total tannins. The results of the evaluation of the antioxidant properties of commercial pomegranate juices can be used in the development of functional beverages.
KEYWORDS
pomegranate juice, brands, total phenolic compounds, total flavonoids, total anthocyanins, total tannins, vitamin C, antioxidant activity
RESEARCH ON TRAITS OF SUBSTANCES AND AGRIBUSINESS PRODUCTS
Оценка антиоксидантных свойств коммерческих гранатовых соков
Санкт-Петербургский политехнический университет
Л. П. Нилова, С. М. Малютенкова, П. С. Лебедева
КОРРЕСПОНДЕНЦИЯ: Нилова, Л.П.
Адрес: Санкт-Петербург, Политехническая улица, д. 29, 195251, Россия
E-mail: nilova_l_p@mail.ru
ЗАЯВЛЕНИЕ О ДОСТУПНОСТИ ДАННЫХ:
данные текущего исследования доступны по запросу у корреспондирующего автора.
ДЛЯ ЦИТИРОВАНИЯ:
Нилова, Л.П., Малютенкова, С.М., &Ле-бедева, П.С. (2023). Роль биологически активных веществ в формировании антиоксидантных свойств гранатового сока. Хранение и переработка сельхозсырья, (1), 83-96. https://doi. org/10.36107/spfp.2023.401
ПОСТУПИЛА: 23.01.2023 ПРИНЯТА: 06.03.2023 ОПУБЛИКОВАНА: 30.03.2023
КОНФЛИКТ ИНТЕРЕСОВ:
авторы сообщают об отсутствии конфликта интересов.
АННОТАЦИЯ
Введение. Гранатовый сок среди потребителей считается одним из самых полезных для здоровья. Ограниченное производство гранатов в России не может обеспечить потребности российских потребителей соками собственного производства. Гранатовые соки производят из концентратов или пастеризованных соков прямого отжима, импортируемых из разных стран, информация об их антиоксидантных свойствах отсутствует.
Цель. Исследовать содержания основных биологически активных веществ и антиокси-дантной активности гранатового сока различных брендов, реализуемых на потребительском рынке, и их влияние на формирование антиоксидантных свойств.
Материалы и методы. Объектами исследований являлись свежеотжатый сок из плодов граната (контроль) и образцы коммерческих гранатовых соков, выработанные по разным технологиям: прямого отжима «Grande»; «Benature»; «Grante»; восстановленного гранатового сока «Swell»; «ОКей»; «Rich»; «GoldBrand»; восстановленного сока с добавлением сока прямого отжима «Nar». В соках определяли общее содержание фенольных соединений, антоцианов, флавоноидов, танинов и витамин С. Антиоксидантная активность соков была определена двумя методами: FRAP и кулонометрическим титрованием, по результатам измерений которых, был рассчитан антиоксиданный индекс.
Результаты. Соки промышленного производства значительно различались количеством биологически активных веществ, разброс значений которых между соками составлял 40-50%,содержали значительно меньше антоцианов и флавоноидов, чем свежеотжатый сок. В составе фенольных соединений всех соков преобладали танины (40-75 %). Антиоксидантная активность соков изменялась в зависимости от метода определения. FRAP-тест показал самые высокие значения антиоксидантной активности у восстановленного гранатового сока «Rich», а кулонометрическое титрование - у гранатового сока прямого отжима «Benature».Наиболее высоким антиоксидантным индексом отличались соки Rich>Benature>Grante, значения которых были больше 85%. Антиоксидантные свойства гранатовых соков зависят от общего количества фенольных соединений (R 2>0,772) и танинов (R 2> 0,538).
Выводы. Формирование антиоксидантных свойств гранатовых соков происходит под влиянием общих фенольных соединений и танинов. Результаты оценки антиоксидант-ных свойств коммерческих гранатовых соков могут быть использованы при разработке функциональных напитков.
КЛЮЧЕВЫЕ СЛОВА
гранатовый сок, бренды, фенольные соединения, флавоноиды, антоцианы, танины, витамин С, антиоксидантная активность
INTRODUCTION
Among fruit juices, pomegranate juice is in particular demand among consumers due to its high taste properties and established opinion of its health benefits. In many countries of the world, pomegranate fruits and pomegranate juice are recommended for strengthening the immune status and preventing cardiovascular, oncological, degenerative and other diseases (Karoma-tov et al., 2018; Sahar et al., 2019; Morittu et al., 2020; Pepe et al., 2020; Khalimova, 2022). Pomegranate fruits and juice are classified as "super fruits" rich in antioxidants (Martins et al., 2019; Hegazi et al., 2021). Its antioxidant activity can be up to three times that of red wine and green tea (Gil et al., 2000). The antioxidant properties of pomegranate juice are provided by various groups of phenolic compounds — flavonoids, anthocyanin, condensed and hydrolysable tannins, phenolic acids, which make up the majority of known bioactive compounds. The high variability in the quantitative composition of pomegranate phenolic compounds under the influence of internal and external factors, juice production technology did not allow the European Food Safety Authority (EFSA) to establish a causal relationship between the consumption of pomegranate juice and the submitted claims for its health benefits (Giménez-Bastida et al., 2021).
The composition of biologically active substances of pomegranate fruits
Nowadays, more than 500 compounds have been isolated and identified from pomegranate fruits, including ellagitannins, gallotannins, anthocyanin, flavanol-an-thocyanin adducts, flavonoids, phenolic acids, and other phenolic compounds (Yisimayili & Chao, 2022). The amount of the main phenolic compounds in pomegranate fruits varies greatly depending on the botanical variety and growing location (Türkyilmaz & Ozkan, 2014; Nuncio-Jáuregui et al., 2015; Legua, et al., 2016; Topalovic et al., 2020). Juice wild-growing pomegranates can contain 4387-8461 mg/l of phenolic compounds, and exceed their amount in cultivated varieties by five or more times (Topalovic et al., 2020).
The total phenolic content in pomegranate juice of cultivated varieties depends both on the botanical variety and on the place of growth and varies: in Spain — 900-1450 mg/L (Legua et al., 2016; Topalovic et al., 2020); in Florida — 365.7-1167.4 mg/L (Shahkooma-
hally et al., 2021); in North Africa - 2890-4500 mg/L (Fawole et al., 2012). Pomegranate fruits cultivated in Iran (5264-7874 mg/L) and China (3151-7428 mg/L) contain the most phenolic compounds (Zarei et al., 2010; Li et al., 2015; Asadi-Gharneh et al., 2017).
The composition of phenolic compounds is affected by the amount of solar energy received in the process of fruit growth. On the example of pomegranate juice of the "Dentedi Cavallo" variety grown in different regions of Sicily, differences in the content of certain groups of phenolic compounds depending on the cardinal direction were established. The maximum amount of flavonoids and anthocyanin contains juice from pomegranates grown in the south of Sicily, tannins - in the west, hexosides of phenolic acids - in the north. The juice from pomegranates grown on the western side contains the least phenolic compounds (Di Stefanoe-tal et al., 2020). Botanical varieties of pomegranates of the same name grown in China and Spain differ in the amount of anthocyanins with a predominance in Chinese fruits (Chen et al, 2022).
During the ripening of pomegranate fruits, the amount of individual phenolic compounds changes: the content of tannins decreases by 6-27 %, while the content of flavonoids and anthocyanin increases by 3.2-3.5 and 1.5-2 times, respectively (Mphahl-ele et al., 2014). There is the evidence of more pronounced changes as pomegranate fruits ripen — a decrease in phenolic compounds by 3-7 times due to the hydrolysis of tannins and the content of ellagic acid and its derivatives. It reduces their antioxidant activity: test with ABTS (2.2'-azinobis (3 -ethylbenzi-hiazoline)-6-sulfonic acid) and DPPH (diphenilpicryl-hydrazil) radicals — 1.6-2.0 times, FRAP test (Ferric reducing antioxidant power) — 5 times (Legua et al., 2016; Nuncio-Jauregui et al., 2015).
The influence of technology on the antioxidant properties of pomegranate juices
The amount of phenolic antioxidants and the antioxi-dant activity of pomegranate juice also depend on the technology (direct squeezing, reconstituted, cold bottling, alternative technologies) (Tezcan et al., 2009; Turkyilmaz & Ozkan, 2014; Conidi et al., 2020; Di Stefano et al., 2020). As a result, commercial varieties of pomegranate juice differ significantly in the content of total phenolic compounds and their individual repre-
sentatives (Tezcan et al., 2009; Mphahlele et al., 2014; Li et al., 2015; Mphahlele et al., 2016; Morittu et al., 2020; Esposto et al., 2021). This has a direct impact on its antioxidant activity and, accordingly, therapeutic and prophylactic properties.
Pomegranate juice can be obtained by squeezing whole fruits or halves, from bags arils or pomegranate arils plus seeds, which affects the composition of phenolic compounds. When using whole fruits for squeezing juice, it contains less flavonoids compared to juice from half fruits, and there are more a monomeric anthocyanins. The largest amount of phenolic compounds passes into the juice from pomegranate halves due to tannins, the amount of which increases by 1.7 times compared to juice from pomegranate seeds and increases antioxidant activity by 2.2 times (Mphahlele et al., 2016). Compared with juice from pomegranate arils plus seeds, the content of hydro-lysable tannins in juice from whole fruits increases by 6.55 times, increasing the antioxidant activity of juices by 21.8 % (Muhacir-Guzel et al., 2014). With the increase in the duration of pressing and the increase in pressure, a more intense transition of tannins occurs. Strong positive linear correlations were found between pressing pressure and antioxidant activity (r = 0.973) and total phenolic content (r = 0.979) (Turkyilmaz et al., 2013).
Freshly pressed juice made from pomegranate seeds contains more anthocyanins and significantly less condensed tannins and ellagic acid than commercial juice from concentrates. The amount of hydrolyzable tannins remains almost the same regardless of the method of juice production (Gil et al., 2000).
Further changes in the composition of phenolic compounds in pomegranate juices can occur during their purification and heat treatment. Sedimentation leads to a greater loss of tannins (more than 50 %), the amount of anthocyanins decreases by 4-6 % (Muha-cir-Guzel et al., 2014; Erkan-Koc et al., 2015). When clarifying juices with polysaccharide-based agents (chitosan, xanthan gum), the loss of phenolic compounds is higher than with protein-based agents (albumin, casein, gelatin), reducing the antioxidant activity of juices by 2.4-26.6 % (Erkan-Koc et al., 2015). Losses of phenolic antioxidants can be less when membrane technologies are used for clarification of pomegranate juice: for polyphenols, flavonoids and anthocyanins they are no more than 4 %. Largely, when using mem-
brane technologies, vitamin C is destroyed — by 32 % (Morittu et al., 2020).
Pasteurization of juices leads to further losses of biologically active substances, especially vitamin C — up to 50 %, and for some phenolic acids (gallic, chloro-genic), campferol, rutin, catechins exceed 50 % (Aky-ildiza et al., 2020). Anthocyanin losses are 8-14 % for non-clarified juices and about 2 % for clarified ones (Vegara et al., 2013).
Changes in the antioxidant properties of pomegranate juices during storage
Antioxidant properties of pomegranate juices depend not only on raw materials and juice technology, but also on the type of packaging and storage conditions before and after bottling. The influence of technology on the change in the content of phenolic antioxidants during storage of juices has been established. In clarified juices, when stored under different conditions for 6 months, the content of total phenolic compounds practically does not change, in contrast to non-clarified ones, in which it drops sharply, especially under the influence of light (Mena et al., 2014). High-temperature pasteurization during further storage of pomegranate juices contributes to a lower loss of total phenolic compounds and vitamin C than long-term low-temperature pasteurization. Anthocyanins, ellagitannins and punicalagin are the first to degrade. For 120 days of storage of pomegranate juices at +5°C before bottling, more than 40 % of anthocyanins degrade (Vegara et al., 2013). After bottling into consumer packaging, the degradation of anthocyanins continues, because of which their amount can be only 35-40 % of the original content before bottling (Gafizov & Gafizov, 2015). Anthocyanin monoglucosides are the most unstable (Mena et al., 2014).
The influence of the type of consumer packaging on the change in the content of phenolic antioxidants in pomegranate juice is ambiguous. According to Pérez-Vicente et al. (Pérez-Vicente et al., 2004) the type of consumer packaging has a significant impact on the degradation of anthocyanins. When storing pomegranate juice in bottles of transparent and green glass for 160 days at room temperature, the degradation of anthocyanins was 77-78 %, and in paperboard carton with polyethylene layers (Minibrik-200) — 95 %. At the same time, the degradation of total phenolic com-
pounds was 20 %, regardless of the type of consumer packaging of pomegranate juice. An increase in storage temperature and exposure to light do not significantly affect the change in the content of total phenolic compounds and the antioxidant activity determined by the TEAC and FRAP methods of pomegranate juice (Mena et al., 2014).
Freshly pressed, cold-pressed and unpressurized juices are associated by consumers with healthy and natural products (Martins et al., 2019). This is facilitated by studies of the antioxidant properties of commercial pomegranate juices in a number of countries and the publication of the results in the open press (Tezcan et al., 2009; Esposto et al., 2021). In Russia, studies of the antioxidant properties of commercial pomegranate juices have not been conducted. TR TS 022/2011 "Food products in terms of their labeling" do not provide for information on the content of natural antioxidants in juices in the labeling. The situation is complicated by the fact that in Russia the production of pomegranates is limited and cannot meet the needs of Russian consumers with juices of its own production. Pomegranate juices are imported or produced from concentrates or pasteurized direct-squeezes juices after storage. The variability of the content of biologically active substances in pomegranate juices and the lack of informa-
tion about their content in various types of commercial pomegranate juices does not allow recommending them to the consumer as a healthy drink.
The aim of the research was to determine the content of the main biologically active substances of pomegranate juice of various brands sold on the consumer market and their influence on the formation of antioxidant properties.
MATERIALS AND METHODS
Objects of study
To conduct research in the retail trade of St. Petersburg, samples of pomegranate juice were purchased, made using different technologies (Table 1). All direct-squeezed juices were produced in the second half of September 2022 according to the information in the labeling. Reconstituted juices were selected with the date of production, so that the period of their presence in retail trade until the time of research was comparable to direct-squeezed juices and did not exceed 30 days. Freshly pressed pomegranate juice from Azerbaijan was used as a control. Juice was pressed from pomegranate seeds.
Table 1
Samples of commercial pomegranate juice
Type of juice
Brand Producer Country
Grande LLC "NAR", city Slantsy, Leningrad region Russia
Benature LLC "Azgranata" Azerbaijan
Grante CJSC "Aznar" Azerbaijan
Swell PC "Leader", Moscow region, Lyubertsy Russia
O'KeM LLC "NAR", city Slantsy, Leningrad region Russia
Rich JSC "Multon", St. Petersburg Russia
Pomegranate direct-squeezed juice
Pomegranate reconstituted juice
LLC "AZ-SERVICE", Baku, Russia
Gold Brand manufactured by LLC
"ANTARIO-CITY", Moscow Azerbaijan
Pomegranate reconstituted .. ,,... _,, ...
■ ■ . M LLC NAR, city Slantsy, n .
juice with direct-squeezed Nar Russia
Leningrad region
juice
Equipment
Spectrophotometer "UNIC0-2800", USA, glass cuvettes with a layer thickness of 1 cm.
Coulometer "Expert-006-antioxidants", Russia. Methods
In pomegranate juices, the total content of phenolic compounds, anthocyanins, flavonoids, tannins, vitamin C, and antioxidant activity were determined by two methods — FRAP and coulometric titration.
The total content of phenolic compounds was determined spectrophotometrically using the Folin-Cio-calteu reagent, after the reaction of which with the studied juice, the optical density was measured at the wavelength of 750 nm (Tezcan et al., 2009). The calibration curve was built on gallic acid.
The total content of anthocyanins was determined by pH-differentiated spectrophotometry according to GOST 32709-20141. The mass concentration of anthocyanins in terms of cyanidin-3-glucoside in pomegranate juice was determined based on changes in the absorption of light with the wavelength of 510 nm with a change in the acidity of juice solutions pH from 1 to 4.4.
The total content of flavonoids was determined spec-trophotometrically by reaction with aluminum chloride at the wavelength of 420 nm according to GOST R 553 1 2-20 1 22. The calibration curve was built according to the routine.
Total tannins were determined by titration of pomegranate juice with potassium permanganate with the participation of indigo carmine as an indicator according to GOST 19885 - 743.
The determination of vitamin C was carried out by the titrimetric method with a solution of sodium 2.6-dichlorophenolindophenolate according to GOST 24556-894.
Determination of antioxidant activity
Antioxidant activity by the FRAP method (Ferric reducing antioxidant power) was determined by the ability of ferric chloride (III) to oxidize antioxidants. In this case, ferric chloride (III) is reduced to ferric chloride (II), the amount of which is determined by the change in color intensity when 0-phenanthro-line is added. The light absorption of the extract was measured at the wavelength of 505 nm against a solution of 96 % ethanol on the UNIC0-2800 spectropho-tometer, USA. Antioxidant activity was determined from the calibration curve and expressed in terms of ascorbic acid5.
Antioxidant activity was determined by coulometric titration on an Expert-006-antioxidants coulometer. As a titrant, electro-generated bromine was used, the electro-generation of which was carried out at a constant current of 50.0 mA from an aqueous 0.2 M solution of potassium bromide in a 0.1 M solution of sulfuric acid with the determination of the end of titration by potentiometric indication. The time, second, spent on titration of the volume of the aliquot of the studied juice, introduced into the measuring cell, was recalculated into the amount of electricity in coulombs. The electrolytic cell of the coulometer was calibrated with ascorbic acid.
The antioxidant index, percentage, of each juice was calculated as the arithmetic mean of the sum of the ranked scores of antioxidant activity determined by different methods. Ranking of scores from 0 to 1 was performed using the Harington desirability function methodological approach. To do this, the maximum value of the antioxidant activity of juices was assigned 1 point, and then the scores for the remaining juices were calculated as the ratio of the value of their antioxidant activity to the maximum value in the data series for each method separately (Madrigal-Carballo et al., 2009; Nilova et al., 2011).
1 GOST 32709-2014. (2014). Juice products. Methods for the determination of anthocyanins. M.: Standartinform.
2 GOST 55312-2012. (2012). Propolis. Methods for determination of flavonoid compounds. M.: Standartinform.
3 GOST 19885-74. (2009). Tea. Methods for determining the content of tannin and caffeine. M.: Standartinform.
4 GOST 24556-89. (2011). Processed products of fruits and vegetables. Methods for determining vitamin C. M.: Standartinform.
5 Rogozhin V.V., Rogozhina T.V. (2016) Workshop on the biochemistry of agricultural products. S-Petersburg: GIORD.
Research Procedure
One pomegranate juice sample was analyzed daily for all parameters according to the methods outlined above; minimizing sample preparation time between analyzes to prevent oxidation of antioxidants.
Data analysis
The studies were carried out in triplicate of two samples of each juice. The results were expressed as mean ± standard deviation. The assessment of the reliability of the results was carried out using the Student's t-test. The difference was considered significant at a probability of 95 %. Pearson correlation coefficient was used to determine the effect of each biologically active substance on antioxidant activity. Statistical processing of experimental data was carried out using the Microsoft Excel 2010 software package.
RESULTS
The content of biologically active substances in commercial pomegranate juices
The studied samples of pomegranate juice significantly differed in the quantitative composition of biologically
active substances (Table 2). Freshly pressed pomegranate juice contained by an order more total anthocya-nins and total flavonoids than industrially manufactured juices, and the amount of vitamin C in it could differ by more than 3 times ("Grande", "O'KeM", "Gold Brand"). The amount of total phenolic compounds and total tannins in all juices was of the same order of magnitude. Despite this, the spread of values for all biologically active substances, even in the series of commercially produced juices, could reach 40-50 %, although there were no statistically significant differences in the data series for some juices. Thus, statistically significant differences were established in the content of: total phenolic compounds between freshly pressed juice and juices "Swell" and "Nar"; total flavonoids between "Benature", "O'KeM" and "Nar" juices; total tannins between freshly pressed juice and "Swell" juice and between "Rich" and "Nar" juice.
In the composition of total phenolic compounds of all studied juice samples, total tannins prevailed, ranging from 40 to 75 %. Their number was not affected by the method of making juices. In direct-squeezed juices, the amount of total tannins was in the range of 166.3-353.3 mg / 100 ml, and in reconstituted juices — 103.9-328.6 mg / 100 ml. The method of making juice did not affect the content of other biologically active substances — total anthocyanins, total flavonoids and vitamin C. For example, direct-squeezed juices contained less total
Table 2
The content of biologically active substances, mg / 100 ml, in various samples of pomegranate juice
Juice Samples Total phenolic compounds Total anthocyanins Total flavonoids Total tannins Vitamin C
Freshly-pressed 411.2 ± 8.2 10.59 ± 0.05 25.22 ± 0.60 205.5 ±10.6 40.12 ±1.2
Direct-squeezed juice brands:
Grande 280.5 ± 6.8 0.64 ± 0.01 7.68 ± 0.20 166.3± 8.3 12.8± 0.2
Benature 494.8 ± 6.2 0.68 ± 0.02 6.26 ± 0.10 290.9±7.5 31.3 ±0.7
Grante 468.0 ± 7.6 0.50 ± 0.02 13.90 ± 0.65 353.3±5.6 24.4± 0.4
Reconstituted juice brands:
Swell 426.1 ± 8.0 1.27 ± 0.04 16.0 ± 0.20 187.0±9.0 29.4±0.3
O'KeR 304.7 ± 6.0 1.00 ± 0.04 6.21 ± 0.25 124.7±3.5 9.6± 0.5
Rich 511.8 ± 9.0 0.31 ± 0.01 16.5 ±0.20 328.6 ±9.6 20.4 ± 0.6
Gold Brand 222.3 ± 5.5 0.45 ± 0.02 4.93 ± 0.10 103.9±3.5 12.0 ± 0.4
Reconstituted juice with direct-squeezed juice
Nar 418.0 ± 7.0 0.89 ± 0.03 6.45 ± 0.10 311.7±9.0 19.2± 0.9
anthocyanins than reconstituted "Swell" and "О'Кей" juices, but more than reconstituted juices "Rich" and "Gold Brand".
Antioxidant activity of commercial pomegranate juices
The antioxidant activity of juices, as well as the amount of biologically active substances, did not depend on the method of juice production and changed in a series of values obtained by the FRAP method: Rich > Benature > Grante > Swell > freshly pressed juice > О'Кей > Nar > Grande > Gold Brand (Table 3). When using coulometric titration to determine the antioxidant activity of juices, the antioxidant series changed somewhat: Benature > Swell > Grante > Rich > >Nar > freshly pressed juice > О'Кей > Grande > Gold
Brand. For an objective assessment of the antioxidant properties of juices, the antioxidant index was calculated.
Rich>Benature>Grante juices had the highest antiox-idant index, the values of which were more than 85 %. The antioxidant index in the range of 50-85 % had juices: Swell>Nar>freshly pressed juice>0'KeM. The direct-squeezed juice "Grande" and the reconstituted juice "Gold Brand" had an antioxidant index less than 50 % and amounted to 48.7 and 30.45 %, respectively.
Effect of biologically active substances on the antioxidant activity of commercial pomegranate juices.
Establishing the influence of the studied biologically active substances on the antioxidant activity of pomegranate juices is presented in Table 4.
Table 3
Indicators of antioxidant activity of pomegranate juice
Juice samples FRAP, mg / 100 ml Coulometric titration, mg / 100 ml Antioxidant index, %
Freshly pressed 49.10 ± 1.20 69.89 ± 0.80 63.55
Direct-squeezed juice brands
Grande 41.92 ± 1.00 46.98 ± 0.64 48.70
Benature 62.84 ± 1.50 112.91 ± 1.30 91.81
Grante 60.87 ± 1.25 106.31 ± 1.36 87.58
Reconstituted juice brands:
Swell 52.94 ± 0.90 110.68 ± 1.43 84.23
О'Кей 46.55 ± 1.10 48.34 ± 0.90 52.38
Rich 75.15 ± 1.83 97.76 ± 1.15 93.29
Gold Brand 34.63 ± 0.92 16.74 ± 0.65 30.45
Reconstituted juice with direct-squeezed juice
Nar 43.62 ± 1.00 83.00 ± 0.86 65.78
Table 4
Correlation coefficients (R2) between some biologically active substances and indicators of antioxidant activity of the studied samples of pomegranate juice p < 0.05)
Indicators
Total phenolic compounds
Total anthocyanins Total flavonoids
Total tannins
Vitamin C
FRAP 0.772 0.002 0.152 0.538 0.152
Coulometric titration 0.879 0.163 0.131 0.610 0.387
Antioxidant Index 0.934 0.002 0.153 0.649 0.324
Total phenolic compounds (R2 > 0.772) and total tannins (R2 > 0.538) demonstrate the most marked characteristic between the amount of biologically active substances and the antioxidant activity of juices. The low content of total anthocyanins and flavonoids in commercial pomegranate juices produced using different technologies does not allow us to determine their effect on antioxidant activity.
DISCUSSION OF THE RESULTS
A significant spread of values in the content of biologically active substances in the studied pomegranate juices is not accidental. Basically, their bottling was carried out in Russia from direct-squeezed juices or concentrates obtained from different sources, which increases the uncertainty of the influence of botanical varieties of pomegranate, the region of growth and the degree of ripeness of fruits, technology and the duration of transportation and storage of semi-finished products before bottling. Commercial varieties of pomegranate juice can contain total phenolic compounds from 1379 to 10086 mg/L (Mphahlele et al., 2016; Morittu et al., 2020; Esposto et al., 2021).
Total tannins, the amount of which can reach up to 71-85 % (Esposto et al., 2021), dominate the composition of phenolic compounds. Depending on the degree of maturity of pomegranates and the technology for making juices, the content of total tannins in them can vary widely from 1 to 376 mg/100 ml (Turkyil-maz et al., 2013; Li et al., 2015; Khomich et al., 2019). Freshly pressedjuice from pomegranate seeds can contain more than 300 mg/100 ml of tannins (Erkan-Koc et al., 2015). In juice from unripe pomegranate fruits, the amount of total tannins is 4-27 % more than from fruits of full ripeness. Fluctuations depending on the botanical variety of immature pomegranates are 88.7 % (Mphahlele et al., 2014). The use of whole or halved pomegranates for high-pressure pressing increases the amount of total tannins in pomegranate juice (Turkyilmaz et al., 2013; Mphahlele et al., 2014; Mphahlele et al., 2016). Therefore, it is difficult to establish the cause of the scatter in the values of the amount of total tannins in the studied juices. The studied commercial juices differed significantly in total anthocyanin content compared to freshly pressed juice. The total amount of anthocyanins in them ranged from 0.31-1.27 mg / 100 ml, and in freshly pressed juice, it was 10.59 mg / 100 ml. These results are con-
sistent with published scientific studies. The amount of total anthocyanins in freshly pressed pomegranate juice is usually in the range of 10.9-128.4 mg/100 ml. Their content is increased in the juice from mature red pomegranate seeds grown on the sunny side (Vegara et al., 2013; Conidi, et al., 2020; Di Stefano et al., 2020; Yuan et al., 2022). In freshly pressed juice from pomegranate seeds growing in Azerbaijan, the content of total anthocyanins is 13.93-15.35 mg/100 ml (Hafizov & Hafizov, 2021), which is close to the values we obtained in freshly pressed juice from pomegranate seeds. Commercial varieties of pomegranate juice sold in Russia contain total anthocyanins from 0.2 to 2.24 mg/100 ml (Khomich et al., 2019). Differences in total antho-cyanin content between freshly pressed and commercial pomegranate juices may be due to the technological stages of industrial production. Pasteurization at +90 °C reduces the total amount of anthocyanins in clarified pomegranate juice by 5 % and in non-clarified pomegranate juice by 35-40 % (Akyildiz et al., 2020). Commercial juices from concentrates can contain total anthocyanins in the range of 0.8-2.9 mg/L (Esposto et al., 2021). When storing juices before bottling, further degradation of anthocyanins occurs, reducing their amount by 2 times at a temperature of+5°C in 120 days and by 12 times at room temperature in 45 days. At the end of the shelf life before bottling, the anthocyanin content of pomegranate juice can be 1-2 mg/100 ml (Vegara et al., 2013).
Differences in total flavonoid and vitamin C content between freshly pressed juice and commercial types of pomegranate juice were not as significant compared to total anthocyanins. The amount of total flavonoids in pomegranate juices can range from 4.5-142.2 mg/100 ml, increasing in juices from mature pomegranates by 3-4 times (Morittu et al., 2020; Di Stefano et al., 2020). In freshly pressed juice from 10 botanical varieties of pomegranate grown in 4 different regions of China, the amount of total flavonoids ranged from 4.5 to 33.5 mg/100 ml (Li et al., 2015). Commercial juices sold in Russia contain about 10 mg/100 ml of total flavonoids (Khomich et al., 2019).
The content of vitamin C in pomegranate juice can range from 9.0 to 50.0 mg / 100 ml (Mphahlele et al., 2014; Mphahlele et al., 2016; Morittu et al., 2020). Vitamin C is destroyed during pasteurization, the loss of which can reach up to 50 % when pasteurized at +90°C (Akyildiz et al., 2020). Increasing the duration of pasteurization at 95°C from 2 to 3 minutes
reduces the vitamin C content of pomegranate juice by almost 2 times (Bhagat & Chakraborty, 2022). The different content of biologically active substances in pomegranate juice samples influenced the formation of their antioxidant activity, in which tannins played the leading role. Tannins and, first, punicalagins, provide 87 % of the antioxidant activity of pomegranate juice obtained in an industrial way (Gil et al., 2000). The role of tannins in the formation of the antioxidant activity of pomegranate juice was confirmed by studies of the composition of phenolic compounds and antioxidant activity (ABTS, DPPH, FRAP) of ripe and unripe pomegranates of 9 botanical varieties (Nuncio-Jauregui et al., 2015). The antioxidant activity of juice from whole fruits is due mainly to hydrolysable tannins (r = 0.994), and from pomegranate seeds — to condensable tannins (r = 0.956) (Muhacir-Guzel et al., 2014).
CONCLUSIONS
The studies have shown that commercial pomegranate juices presented on the Russian consumer market contain phenolic antioxidants and vitamin C in different amounts, the spread of values between juices being 40-50 %. The composition of phenolic antioxidants of all juices was dominated by total tannins (40-75 %), which influenced the formation of their antioxidant properties (R2=0.649).
Indicators of antioxidant activity of pomegranate juices differ depending on the method of determination, changing the order of significance of juices. The antioxidant index calculated on their basis made it possible to single out three brands of commercial pomegranate juices — Rich>Benature>Grante, with values above 85 %, which can be recommended to consumers as a drink for preventive nutrition.
The obtained results of the quantitative composition of biologically active substances and the antioxidant activity of pomegranate juices will be of interest to researchers in the development of functional drinks, medical workers to recommend juices to patients for a healthy diet.
АВТОРСКИЙ ВКЛАД
Нилова Людмила Павловна — обзор литературных источников по исследуемой проблеме, написала рукопись, проверка на плагиат.
Малютенкова Светлана Михайловна — организация исследований, верификация данных.
Лебедева Полина Сергеевна — проведение исследований.
REFERENCES
Gafizov, G. K., & Gafizov, S. G. (2015). Vliyanie metoda obrabotki i temperatury khraneniya granatovogo soka na sokhrannost' antotsianov [The influence of the processing method and the storage temperature of pomegranate juice on the safety of anthocyanins]. Tekhnicheskie nauki — ot teorii k praktike [Technical Sciences — from Theory to Practice], (2), 59-72.
Karomatov, I. D., Nabieva, Z. T., & Ganiev, R. N. (2018). Plo-dy granatov v profilaktike i lechenii sakharnogo diabeta i serdechno-sosudistykh zabolevanii [Pomegranate fruits in the prevention and treatment of diabetes and cardiovascular diseases]. Biologiya i intergrativnaya meditsina [Biology and Integrative Medicine], (2), 91-100.
Khalimova, D. Zh. (2022). Granat pri zabolevaniyakh nervnoi sistemy (obzor literatury) [Pomegranate in diseases of the nervous system (literature review)]. Biologiya i intergrativnaya meditsina [Biology and Integrative Medicine], (4), 251-278.
Khomich, L. M., Perova, I. B., & Eller, K. I. (2019). Nutrientnyi profil' granatovogo soka [The nutritional profile of pome-
granate juice]. Voprosy pitaniya [Nutrition Issues], 88(5), 80-92. https://doi.org/10.24411/0042-8833-2019-10057
Nilova, L. P., Vytovtov, A. A., Naumenko, N. V., & Kalinina, I. V. (2011). Upravlenie potrebitel'skimi svoistvami obo-gashchennykh pishchevykh produktov [Management of consumer properties of fortified foods]. Vestnik Yuzh-no-Ural'skogo gosudarstvennogo universiteta. Ekonomika i menedzhment [Bulletin of the South Ural State University. Economics and Management], (41), 185-191.
Akyildiz, A., Karaca, E., Agcam, E., Dundar, B., & Cinkir, N. I. (2020). Changes in quality attributes during production steps and frozen-storage of pomegranate juice concentrate. Journal of Food Composition and Analysis, 92, Article 103548. https://doi.org/10.1016Zj.jfca.2020.103548
Asadi-Gharneh, H. A., Mohammadzamani, M., & Karimi, S. (2017). Evaluation of physico-chemical properties and bioactive compounds of some Iranian pomegranate culti-vars. International Journal of Fruit Science, 17(2), 175-187. http://dx.doi.org/10.1080/15538362.2016.1275923
Bhagat, Bh., & Chakraborty, S. (2022). Potential of pulsed light treatment to pasteurize pomegranate juice: Microbial safety, enzyme inactivation, and phytochemical retention. LWT — Food Science and Technology, 159, Article 113215. https://doi.org/10.1016/j.lwt.2022.113215 Chen, Ya., Gao, H., Wang, S., Liu, X., Hu O., Jian, Z., Wan, R., Song, Ji., & Shi, Ji. (2022). Comprehensive evaluation of 20 pomegranate (Punica granatum L.) cultivars in China. Journal of Integrative Agriculture, 21(2), 434-445. https:// doi.org/10.1016/S2095-3119(20)63389-5 Conidi, C., Drioli, E., & Cassano, A. (2020). Perspective of membrane technology in pomegranate juice processing: A review. Foods, 9(7), 889. https://doi.org/10.3390/ foods9070889
Di Stefano, V., Scandurra, S., Pagliaro, A., Di Martino, V., & Melilli, M. G. (2020) Effect of sunlight exposure on an-thocyanin and non-anthocyanin phenolic levels in pomegranate juices by high resolution mass spectrome-try approach. Foods, 9(9), 1161. https://doi.org/10.3390/ foods9091161
Erkan-Koc, B., Türkyilmaz, M., Yemis O., & Ozkan, M. (2015). Effects of various protein- and polysaccharide-based clarification agents on antioxidative compounds and colour of pomegranate juice. Food Chemistry, 184, 37-45. http:// dx.doi.org/10.1016/j.foodchem.2015.03.064 Esposto, S., Veneziani, G., Taticchi, A., Urbani, S., Selvag-gini, R., Sordini, B., Daidone, L., Gironi, G., & Servili, M. (2021). Chemical composition, antioxidant activity, and sensory characterization of commercial pomegranate juices. Antioxidants, 10(9), 1381. https://doi.org/10.3390/ antiox10091381 Fawole, O. A., Opara, U. L., & Theron, K. I. (2012). Chemical and phytochemical properties and antioxidant activities of three pomegranate cultivars grown in South Africa. Food and Bioprocess Technology, 5, 2934-2940. https:// doi.org/10.1007/s11947-011-0533-7
Gil, M. I., Tomás-Barberán, F. A., Hess-Pierce, B., Hol-croft, D. M., & Kader, A. A. (2000). Antioxidant activity of pomegranate juice and its relationship with phenolic composition and processing. Journal of Agricultural and Food Chemistry, 48(10), 4581-4589. https://doi. org/10.1021/jf000404a Giménez-Bastida, Ju. A., Avila-Gálvez, M. A., Espín, Ju. C., & González-Sarrias, A. (2021). Evidence for health properties of pomegranate juices and extracts beyond nutrition: A critical systematic review of human studies. Trends in Food Science & Technology, 114, 410-423. https://doi. org/10.1016/j.tifs.2021.06.014 Hafizov, S., & Hafizov, G. (2021). Descriptive values for analytical properties of freshly squeezed and pasteurized pomegranate juices. Sciences of Europe, 66, 36-42.
Hegazi, N. M., El-Shamy, Sh., Fahmy, H., & Farag, M. A. (2021). Pomegranate juice as a super-food: A comprehensive review of its extraction, analysis, and quality assessment approaches. Journal of Food Composition and Analysis, 97, Article 103773. https://doi.org/10.1016/j. jfca.2020.103773
Legua, P., Forner-Giner, M. Á., Nuncio-Jáuregui, N., & Hernández, F. (2016). Polyphenolic compounds, anthocyanins and antioxidant activity of nineteen pomegranate fruits: A rich source of bioactive compounds. Journal of Functional Foods, 23, 628-636. http://dx.doi.org/10.1016/j. jff.2016.01.043
Li, X., Wasila, H., Liu, L., Yuan, T., Gao, Z., Zhao, B., & Ahmad, I. (2015). Physicochemical characteristics, polyphenol compositions and antioxidant potential of pomegranate juices from 10 Chinese cultivars and the environmental factors analysis. Food Chemistry, 175, 575-584. https://doi. org/10.1016/j.foodchem.2014.12.003
Madrigal-Carballo, S., Rodriguez, G., Krueger, C.G., Dreher, M. J., & Reed, D. (2009). Pomegranate (Punica granatum) supplements: Authenticity, antioxidant and polyphenol composition. Journal of Functional Foods, 1(3), 1324-1329. https://doi.org/10.1016/j.jff.2009.02.005
Martins, I. B. A., Oliveira, D., Rosenthal, A., Ares, G., & Deliza, R. (2019). Brazilian consumer's perception of food processing technologies: A case study with fruit juice. Food Research International, 125, Article 108555. https:// doi.org/10.1016/j.foodres.2019.108555
Mena, P., Martí, N., & García-Viguera, C. (2014) The Impact of Processing and Storage on the (Poly)Phenolic Fraction of Pomegranate (Punica granatum L.) Juices. In Processing and Impact on Antioxidants in Beverages (pp. 173-184). Academic Press. https://doi.org/10.1016/B978-0-12-404738-9.00018-0
Morittu, V. M., Mastellone, V., Tundis, R., Loizzo, M. R., Tu-disco, R., Figoli, A., Cassano, A., Musco, N., Britti, D., In-fascelli, F., & Lombardi, P. (2020). Antioxidant, biochemical, and in-life effects of punica granatum L. natural juice vs. clarified juice by polyvinylidene fluoride membrane. Foods, 9(2), 242. https://doi.org/10.3390/foods9020242
Mphahlele, R. R., Fawole, O. A., Mokwena, L. M., & Opara, U. L. (2016). Effect of extraction method on chemical, volatile composition and antioxidant properties of pomegranate juice. South African Journal of Botany, 103, 135144. https://doi.org/10.1016/j.sajb.2015.09.015
Mphahlele, R. R., Stander, M. A., Fawole, O. A., & Opara, U. L. (2014). Effect of fruit maturity and growing location on the postharvest contents of flavonoids, phenolic acids, vitamin C and antioxidant activity of pomegranate juice (cv. Wonderful). Scientia Horticulturae, 179, 36-45. https://doi.org/10.1016/j.scienta.2014.09.007
Muhacir-Güzel, N., Türkyilmaz, M., Yemis, O., Tagi, S., & Ozkan, M. (2014). Changes in hydrolysable and condensed tannins of pomegranate (Punica granatum L., cv. Hica-znar) juices from sacs and whole fruits during production and their relation with antioxidant activity. LWT — Food Science and Technology, 59, 933-940. http://dx.doi. org/10.1016/j.lwt.2014.07.025
Nuncio-Jáuregui, N., Nowicka, P., Munera-Picazo, S., Hernández, F., Carbonell-Barrachina, Á. A., & Wojdylo, A. (2015). Identification and quantification of major derivatives of ellagic acid and antioxidant properties of thinning and ripe Spanish pomegranates. Journal of Functional Foods, 12, 354-364. http://dx.doi.org/10.1016/j.jff.2014.11.007
Pepe, G., Rapa, S. F., Salviati, E., Bertamino, A., Auriemma, G., Cascioferro, S., Autore, G., Ouaroni, A., Campiglia, P., & Marzocco, S. (2020). Bioactive polyphenols from pomegranate juice reduce 5-fluorouracil-induced intestinal mucositis in intestinal epithelial cells. Antioxidants, 9(8), 699. https://doi.org/10.3390/antiox9080699 Pérez-Vicente, A., Serrano, P., Abellán, P., & García-Viguera, C. (2004). Influence of packaging material on pomegranate juice colour and bioactive compounds, during storage. Journal of the Science of Food and Agriculture, 84, 639-644. https://doi.org/10.1002/jsfa.1721 Sahar, A., Rahman, U., Ishaq A., Munir, M. S., & Aadil, R. M. (2019). Health-Promoting Perspectives of Fruit-Based Functional Energy Beverages. Sports and Energy Drinks, 10, 399-439. https://doi.org/10.1016/B978-0-12-815851-7.00012-7
Shahkoomahally, Sh., Khadivi, A., Brechta, J. K., & Sarkhosh, A. (2021). Chemical and physical attributes of fruit juice and peel of pomegranate genotypes grown in Florida, USA. Food Chemistry, 342, Article 128302. https://doi. org/10.1016/j.foodchem. 128302 Tezcan, F., Gultekin-Ozguven, M., Diken, T., Ozcelik, B., & Erim, F. B. (2009). Antioxidant activity and total phenolic, organic acid and sugar content in commercial pomegranate juices. Food Chemistry, 115, 873-877. https://doi. org/10.1016/j.foodchem.2008.12.103 Topalovic, A., Knezevic, M., Gacnik, S., &Mikulic-Petk-ovsek, M. (2020). Detailed chemical composition of juice from autochthonous pomegranate genotypes (Punica granatum L.) grown in different locations in Montenegro. Food Chemistry, 330, Article 127261. https://doi. org/10.1016/j.foodchem.2020.127261
Turkyilmaz, M., & Ozan, M. (2014). Effects of condensed tannins on anthocyanins and colour of authentic pomegranate (Punica granatum L.) juices. Food Chemistry, 164, 324331. http://dx.doi.org/10.1016Zj.foodchem.2014.05.048
Turkyilmaz, M., Tagi, §., Dereli, U., & Ozkan, M. (2013). Effects of various pressing programs and yields on the an-tioxidant activity, antimicrobial activity, phenolic content and colour of pomegranate juices. Food Chemistry, 138(2-3), 1810-1818. https://doi.org/10.1016Zj.food-chem.2012.11.100 Vegara, S., Mena, P., Marti, N., Saura, D., & Valero, M. (2013). Approaches to understanding the contribution of an-thocyanins to the antioxidant capacity of pasteurized pomegranate juices. Food Chemistry, 141(3), 1630-1636. https://doi.org/10.1016/j.foodchem.2013.05.015 Yisimayili, Z., & Chao, Zh. (2022). A review on phytochemi-cals, metabolic profiles and pharmacokinetics studies of the different parts (juice, seeds, peel, flowers, leaves and bark) of pomegranate (Punica granatum L.). Food Chemistry, 395, Article 133600. https://doi.org/10.1016/j.food-chem.2022.133600 Yuan, L., Cheng, F., Yi, J., Cai, S., Liao, X., Lao, F., & Zhou, L. (2022). Effect of high-pressure processing and thermal treatments on color and in vitro bioaccessibility of anthocyanin and antioxidants in cloudy pomegranate juice. Food Chemistry, 373, Article 131397. https://doi. org/10.1016/j.foodchem.2021.131397
Zarei, M., Azizi., M., & Bashiri-Sadr, Z. (2010). Studies on Physico-Chemical Properties and Bioactive Compounds of Six Pomegranate Cultivars Grown in Iran. Journal of Food Technology, 8(3), 112-117. https://doi.org/10.3923/ jftech.2010.112.117
ЛИТЕРАТУРА
Гафизов, Г. К., & Гафизов, С. Г. (2015). Влияние метода обработки и температуры хранения гранатового сока на сохранность антоцианов. Технические науки — от теории к практике, (2), 59-72.
Кароматов, И. Д., Набиева, З. Т., & Ганиев, Р. Н. (2018). Плоды гранатов в профилактике и лечении сахарного диабета и сердечно-сосудистых заболеваний. Биология и интергративная медицина, (2), 91-100.
Нилова, Л. П., Вытовтов, А. А., Науменко, Н. В., & Калинина, И. В. (2011). Управление потребительскими свойствами обогащенных пищевых продуктов. Вестник Южно-Уральского государственного университета. Экономика и менеджмент, (41), 185-191.
Халимова, Д. Ж. (2022). Гранат при заболеваниях нервной системы (обзор литературы). Биология и интергра-тивная медицина, (4), 251-278.
Хомич, Л. М., Перова, И. Б., & Эллер, К. И. (2019). Нутри-ентный профиль гранатового сока. Вопросы питания, 88(5), 80-92. https://doi.org/10.24411/0042-8833-2019-10057
Akyildiz, A., Karaca, E., Agcam, E., Dundar, B., & Cinkir, N. I. (2020). Changes in quality attributes during production steps and frozen-storage of pomegranate juice concentrate. Journal of Food Composition and Analysis, 92, Article 103548. https://doi.org/10.10Wj.jfca.2020.103548 Asadi-Gharneh, H. A., Mohammadzamani, M., & Karimi, S. (2017). Evaluation of physico-chemical properties and bioactive compounds of some Iranian pomegranate culti-vars. International Journal of Fruit Science, 17(2), 175-187. http://dx.doi.org/10.1080/15538362.2016.1275923 Bhagat, Bh., & Chakraborty, S. (2022). Potential of pulsed light treatment to pasteurize pomegranate juice: Micro-bial safety, enzyme inactivation, and phytochemical retention. LWT — Food Science and Technology, 159, Article 113215. https://doi.org/10.1016/j.lwt.2022.113215 Chen, Ya., Gao, H., Wang, S., Liu, X., Hu Q., Jian, Z., Wan, R., Song, Ji., & Shi, Ji. (2022). Comprehensive evaluation of 20 pomegranate (Punica granatum L.) cultivars in China. Journal of Integrative Agriculture, 21(2), 434-445. https:// doi.org/10.1016/S2095-3119(20)63389-5
Conidi, C., Drioli, E., & Cassano, A. (2020). Perspective of membrane technology in pomegranate juice processing: A review. Foods, 9(7), 889. https://doi.org/10.3390/ foods9070889
Di Stefano, V., Scandurra, S., Pagliaro, A., Di Martino, V., & Melilli, M. G. (2020) Effect of sunlight exposure on an-thocyanin and non-anthocyanin phenolic levels in pomegranate juices by high resolution mass spectrome-try approach. Foods, 9(9), 1161. https://doi.org/10.3390/ foods9091161
Erkan-Koc, B., Türkyilmaz, M., Yemis O., & Ozkan, M. (2015). Effects of various protein- and polysaccharide-based clarification agents on antioxidative compounds and colour of pomegranate juice. Food Chemistry, 184, 37-45. http:// dx.doi.org/10.1016/j.foodchem.2015.03.064 Esposto, S., Veneziani, G., Taticchi, A., Urbani, S., Selvag-gini, R., Sordini, B., Daidone, L., Gironi, G., & Servili, M. (2021). Chemical composition, antioxidant activity, and sensory characterization of commercial pomegranate juices. Antioxidants, 10(9), 1381. https://doi.org/10.3390/ antiox10091381 Fawole, O. A., Opara, U. L., & Theron, K. I. (2012). Chemical and phytochemical properties and antioxidant activities of three pomegranate cultivars grown in South Africa. Food and Bioprocess Technology, 5, 2934-2940. https:// doi.org/10.1007/s11947-011-0533-7 Gil, M. I., Tomás-Barberán, F. A., Hess-Pierce, B., Hol-croft, D. M., & Kader, A. A. (2000). Antioxidant activity of pomegranate juice and its relationship with phenolic composition and processing. Journal of Agricultural and Food Chemistry, 48(10), 4581-4589. https://doi. org/10.1021/jf000404a
Giménez-Bastida, Ju. A., Avila-Gálvez, M. A., Espín, Ju. C., & González-Sarrias, A. (2021). Evidence for health properties of pomegranate juices and extracts beyond nutrition: A critical systematic review of human studies. Trends in Food Science & Technology, 114, 410-423. https://doi. org/10.1016/j.tifs.2021.06.014 Hafizov, S., & Hafizov, G. (2021). Descriptive values for analytical properties of freshly squeezed and pasteurized pomegranate juices. Sciences of Europe, 66, 36-42.
Hegazi, N. M., El-Shamy, Sh., Fahmy, H., & Farag, M. A. (2021). Pomegranate juice as a super-food: A comprehensive review of its extraction, analysis, and quality assessment approaches. Journal of Food Composition and Analysis, 97, Article 103773. https://doi.org/10.1016/j. jfca.2020.103773 Legua, P., Forner-Giner, M. Á., Nuncio-Jáuregui, N., & Hernández, F. (2016). Polyphenolic compounds, anthocyanins and antioxidant activity of nineteen pomegranate fruits: A rich source of bioactive compounds. Journal of Functional Foods, 23, 628-636. http://dx.doi.org/10.1016/j. jff.2016.01.043
Li, X., Wasila, H., Liu, L., Yuan, T., Gao, Z., Zhao, B., & Ahmad, I. (2015). Physicochemical characteristics, polyphenol compositions and antioxidant potential of pomegranate juices from 10 Chinese cultivars and the environmental factors analysis. Food Chemistry, 175, 575-584. https://doi. org/10.1016/j.foodchem.2014.12.003
Madrigal-Carballo, S., Rodriguez, G., Krueger, C.G., Dreher, M. J., & Reed, D. (2009). Pomegranate (Punica gra-natum) supplements: Authenticity, antioxidant and polyphenol composition. Journal of Functional Foods, 1(3), 1324-1329. https://doi.org/10.1016/jjff.2009.02.005 Martins, I. B. A., Oliveira, D., Rosenthal, A., Ares, G., & Deliza, R. (2019). Brazilian consumer's perception of food processing technologies: A case study with fruit juice. Food Research International, 125, Article 108555. https:// doi.org/10.1016/j.foodres.2019.108555 Mena, P., Martí, N., & García-Viguera, C. (2014) The Impact of Processing and Storage on the (Poly)Phenolic Fraction of Pomegranate (Punica granatum L.) Juices. In Processing and Impact on Antioxidants in Beverages (pp. 173-184). Academic Press. https://doi.org/10.1016/B978-0-12-404738-9.00018-0 Morittu, V. M., Mastellone, V., Tundis, R., Loizzo, M. R., Tu-disco, R., Figoli, A., Cassano, A., Musco, N., Britti, D., In-fascelli, F., & Lombardi, P. (2020). Antioxidant, biochemical, and in-life effects of punica granatum L. natural juice vs. clarified juice by polyvinylidene fluoride membrane. Foods, 9(2), 242. https://doi.org/10.3390/foods9020242
Mphahlele, R. R., Fawole, O. A., Mokwena, L. M., & Opa-ra, U. L. (2016). Effect of extraction method on chemical, volatile composition and antioxidant properties of pomegranate juice. South African Journal of Botany, 103, 135144. https://doi.org/10.1016Zj.sajb.2015.09.015
Mphahlele, R. R., Stander, M. A., Fawole, O. A., & Opara, U. L. (2014). Effect of fruit maturity and growing location on the postharvest contents of flavonoids, phenolic acids, vitamin C and antioxidant activity of pomegranate juice (cv. Wonderful). Scientia Horticulturae, 179, 36-45. https://doi.org/10.1016/j.scienta.2014.09.007 Muhacir-Güzel, N., Türkyilmaz, M., Yemis, O., Tagi, S., & Ozkan, M. (2014). Changes in hydrolysable and condensed tannins of pomegranate (Punica granatum L., cv. Hica-znar) juices from sacs and whole fruits during production and their relation with antioxidant activity. LWT — Food Science and Technology, 59, 933-940. http://dx.doi. org/10.1016/j.lwt.2014.07.025 Nuncio-Jáuregui, N., Nowicka, P., Munera-Picazo, S., Hernández, F., Carbonell-Barrachina, Á. A., & Wojdylo, A. (2015). Identification and quantification of major derivatives of ellagic acid and antioxidant properties of thinning and ripe Spanish pomegranates. Journal of Functional Foods, 12, 354-364. http://dx.doi.org/10.1016/jjff.2014.11.007 Pepe, G., Rapa, S. F., Salviati, E., Bertamino, A., Auriemma G., Cascioferro, S., Autore, G., Ouaroni, A., Campiglia, P., & Marzocco, S. (2020). Bioactive polyphenols from pomegranate juice reduce 5-fluorouracil-induced intestinal mucositis in intestinal epithelial cells. Antioxidants, 9(8), 699. https://doi.org/10.3390/antiox9080699
Pérez-Vicente, A., Serrano, P., Abellán, P., & García-Viguera, C. (2004). Influence of packaging material on pomegranate juice colour and bioactive compounds, during storage. Journal of the Science of Food and Agriculture, 84, 639-644. https://doi.org/10.1002/jsfa.1721
Sahar, A., Rahman, U., Ishaq, A., Munir, M. S., & Aadil, R. M. (2019). Health-Promoting Perspectives of Fruit-Based
Functional Energy Beverages. Sports and Energy Drinks, 10, 399-439. https://doi.org/10.1016/B978-0-12-815851-7.00012-7
Shahkoomahally, Sh., Khadivi, A., Brechta, J. K., & Sark-hosh, A. (2021). Chemical and physical attributes of fruit juice and peel of pomegranate genotypes grown in Florida, USA. Food Chemistry, 342, Article 128302. https://doi. org/10.1016/j.foodchem. 128302 Tezcan, F., Gultekin-Ozguven, M., Diken, T., Ozcelik, B., & Erim, F. B. (2009). Antioxidant activity and total phenolic, organic acid and sugar content in commercial pomegranate juices. Food Chemistry, 115, 873-877. https://doi. org/10.1016/j.foodchem.2008.12.103 Topalovic, A., Knezevic, M., Gacnik, S., &Mikulic-Petk-ovsek, M. (2020). Detailed chemical composition of juice from autochthonous pomegranate genotypes (Punica granatum L.) grown in different locations in Montenegro. Food Chemistry, 330, Article 127261. https://doi. org/10.1016/j.foodchem.2020.127261
Turkyilmaz, M., & Ozan, M. (2014). Effects of condensed tannins on anthocyanins and colour of authentic pomegranate (Punica granatum L.) juices. Food Chemistry, 164, 324331. http://dx.doi.org/10.1016/j.foodchem.2014.05.048 Turkyilmaz, M., Tagi, §., Dereli, U., & Ozkan, M. (2013). Effects of various pressing programs and yields on the an-tioxidant activity, antimicrobial activity, phenolic content and colour of pomegranate juices. Food Chemistry, 138(2-3), 1810-1818. https://doi.org/10.1016/j.food-chem.2012.11.100
Vegara, S., Mena, P., Marti, N., Saura, D., & Valero, M. (2013). Approaches to understanding the contribution of an-thocyanins to the antioxidant capacity of pasteurized pomegranate juices. Food Chemistry, 141(3), 1630-1636. https://doi.org/10.1016Zj.foodchem.2013.05.015 Yisimayili, Z., & Chao, Zh. (2022). A review on phytochemi-cals, metabolic profiles and pharmacokinetics studies of the different parts (juice, seeds, peel, flowers, leaves and bark) of pomegranate (Punica granatum L.). Food Chemistry, 395, Article 133600. https://doi.org/10.1016/j.food-chem.2022.133600 Yuan, L., Cheng, F., Yi, J., Cai, S., Liao, X., Lao, F., & Zhou, L. (2022). Effect of high-pressure processing and thermal treatments on color and in vitro bioaccessibility of anthocyanin and antioxidants in cloudy pomegranate juice. Food Chemistry, 373, Article 131397. https://doi. org/10.1016/j.foodchem.2021.131397
Zarei, M., Azizi., M., & Bashiri-Sadr, Z. (2010). Studies on Physico-Chemical Properties and Bioactive Compounds of Six Pomegranate Cultivars Grown in Iran. Journal of Food Technology, 8(3), 112-117. https://doi.org/10.3923/ jftech.2010.112.117
