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RESEARCH OF INFLUENCE OF THERMAL PROCESSING AND SUNFLOWER VEGETABLE OIL ADDITION ON FUNCTIONAL PROPERTIES OF MEAT PRODUCTS
Indzhelieva D.T.1, Yorgova K.I.2 Email: Indzhelieva1184@scientifictext.ru
1Indzhelieva Diana Todorova - PhD in Food Technologies, Chief Assistant, COLLEGE OF TOURISM, PROF. DR. ASENZLATAROV UNIVERSITY, BURGAS;
2Yorgova Katya Ivanova - PhD in Food Technologies, Professor, DEPARTMENT OF MEAT AND FISH TECHNOLOGY, TECHNOLOGICAL FACULTY, UNIVERSITY OF FOOD TECHNOLOGIES, PLOVDIV, BULGARIA
Abstract: temperature and duration of cooking process have a large effect on physical properties and eating quality of meat and meat products. The properties of processed meat products such as tenderness, juiciness and perception of flavours during mastication are based on functional properties ofproteins. Manufacturers are currently using a wide range of vegetable additives, such as vegetable oil to improve the functional properties of meat and meat products. The objective of this research was to assess the effect of thermal processing and addition of vegetable oil on the functional properties and sensory characteristics of model meat products. Keywords: meat, meat products, vegetable oil.
ИССЛЕДОВАНИЕ ВЛИЯНИЯ ТЕРМИЧЕСКОЙ ОБРАБОТКИ И ДОБАВЛЕНИЯ ПОДСОЛНЕЧНОГО РАСТИТЕЛЬНОГО МАСЛА НА ФУНКЦИОНАЛЬНЫЕ СВОЙСТВА МЯСНЫХ ПРОДУКТОВ Инджелиева Д.Т.1, Йоргова К.И.2
1Инджелиева Диана Тодорова - кандидат технических наук, главный ассистент,
колледж по туризму, Университет им. проф. д-ра Ас. Златарова, г. Бургас;
2Йоргова Катя Иванова - кандидат технических наук, профессор, кафедра технологии мяса и рыбы, технологический факультет, Университет пищевых технологий, г. Пловдив, Болгария
Аннотация: температура и продолжительность процесса приготовления оказывают большое влияние на физические свойства и вкусовые качества мяса и мясных продуктов. Свойства переработанных мясных продуктов такие, как нежность, сочность и восприятие вкуса при пережевывании, основаны на функциональных свойствах белков. В настоящее время производители используют широкий спектр растительных добавок, таких как растительное масло, для улучшения функциональных свойств мяса и мясных продуктов. Цель данного исследования состояла в том, чтобы оценить влияние термической обработки и добавления растительного масла на функциональные свойства и органолептические характеристики модельных мясных продуктов. Ключевые слова: мясо, мясные продукты, растительное масло.
Introduction
Thermal processing affects production costs, weight losses and sensory attributes and thus has a general effect on the quality of processed meats. Cooking has a large effect on textural properties of meat. This method of thermal processing is defined as the heating of meat to a sufficiently high temperature to denature proteins. Temperature and duration of cooking process have a large effect on physical properties and eating quality of meat and meat products. As the meat is usually cooked
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before being eaten, it is important to understand the physical changes of meat texture during heating. The initial increased in meat toughness in temperature range between 40 and 60°C, could be explained by heat denaturation of myofibrillar proteins, especially myosin. The rise in meat toughness from 65 to 80°C could be attributed to the denaturation of intramuscular collagen. High pressure treatment at different temperatures will induce different effects on meat texture since linkages stabilising the secondary, tertiary and quaternary structures of a protein respond differently to heat and pressure. The properties of processed meat products such as tenderness, juiciness and perception of flavours during mastication are based on functional properties of proteins [2, 4, 5]. In order to improve the functional properties of meat and meat products, manufacturers are currently using a wide range of vegetable additives, such as vegetable oil. The objective of this research was to assess the effect of thermal processing and addition of vegetable oil on the functional properties (cooking loss, physical properties) and sensory characteristics of model meat products.
Materials and methods
The samples of pork meat (m. longissimus lumborum) was obtained from Meat Plant "Goljamo Vranovo" placed near Russe (Bulgaria). The ingredients used in the production of model meat products included: vegetable oil (Biser Oliva AD, Bulgaria), emulsifier 3302-EY21d (Palsgaard, Danmark), curing salt (containing 99.5% sodium chloride and 0.5% sodium nitrite), polyphosphates, sodium isoascorbinate, product "Glutalin", sugar.
Before processing, the meat was portioned and its pH (pH 5.78) was measured. The meat samples were injected with brine solutions to 20% of the raw meat weight. Prior to injection of oil emulsion containing 50% of vegetable oil, 3% emulsifier and 47% water was prepared. To prepare this emulsion oil and water was heated near to 65°C. Next the ingredients of emulsion were prepared by mixing for 30s using a BUCHI "MIXER B - 400" (9000 rev/ min). The oil emulsion was added to brine solution in the amount of 0,30 and 50% in order to deliver 0,3 or 5% of vegetable oil in final products (Tab. 1).
Table 1. Levels of variables
Content of vegetable oil in final products Thermal processing
75°C 85°C 95°C
0% A D G
3% B E H
5% C F I
After injection, the meat samples were weighed and massaged (PEK-MONT M203). The meat products were massaged for 8h at 4°C (4 rev/min). After massaging, the model meat products were heated in scalding vat (PEK-MONT MRA500) to a final internal temperature of 75, 85 or 95°C. Afterwards the samples were cooled to 14°C in an ice bath and stored overnight at 3°C. The following properties were determined in final products: pH values (using Microcomputer CP -551), dry matter content (by thermal drying method in 105°C according to AOAC [1]. The modified Grau-Hamm procedure [1957] was used to measure WHC (Water Holding Capacity) of the model meat products, and was expressed as the ratio of moisture retained in the sample to the initial moisture content. Cooking loss was estimated by the equation: weight before cooking minus weight after cooking/weight before cooking x 100. Sensory evaluation was carried out using ten points scale of intensity and desirability (from 1 point as very slight to 10 points results as very much desirable). All processed meat products were sensory evaluated by 7 panellists. The fallowing sensory parameters were investigated: colour, aroma, flavour, saltiness, juiciness and fragility. For parameters 4, 5, 6, and 7 both intensity and desirability scale were used. The data were analysed statistically, using STATISTICA 6.0 software. Response surface methodology (RSM) was used to study the simultaneous effect of the experimental of thermal processing and addition vegetable oil. Significant differences between the mean values were determined using Duncan's test (a = 0.05).
Results and discussion
The results of the thermal processing on physical properties of model meat products are presented in Table 2.
Table 2. The effect of thermal processing and vegetable oil level on physical properties of model meat
products
Variable Parameters
pH Dry matter, % WHC, % Cooking loss, %
A 6.08a 27.21a 64.69ab 6.1 a
B 6.05a 27.83a 65.16ab 7.4ab
C 6.03a 29.6bc 68.34abc 6.1a
D 6.16b 31.06c 64.8ab 9.3ab
E 6.24c 29.25ab 63.56a 12.4b
F 6.23c 33.47cd 69.85bc 14.6b
G 6.14b 29.33b 72.34c 23.1c
H 6.18b 33.02cd 69.65bc 20.4c
I 6.25c 34.38d 70.82c 24.4c
a, b, c, d - mean values denoted by various letters and placed in the columns are statistically different at p < 0.05.
The pH value of the meat products under investigation ranged from 6.03 to 6.25. The temperature of thermal processing was variable that most influence the pH value. Vegetable oil level had no effect on these properties of the products. The results obtained in the study showed that the temperature of thermal processing and vegetable oil level was responsible for dry matter content. The measurements of dry matter content in meat products showed that the highest content was observed in model meat products with 5% vegetable oil level and heated at 95°C (sample I, 34.38%) and the lowest in sample A and B (27.21 and 27.81%, respectively). The water holding capacity ranged from 63.56 to 70.82%. The highest WHC (sample G and I) was observed in meat samples heated at 95°C and the lowest in sample E, one of the samples with the highest pH value. Cooking loss results are the most important test for the meat industry to predict the behaviour of the products during cooking due to non-meat ingredients or other factors. In the present study cooking losses were not appreciably affected by vegetable oil addition. The amount of cooking loss was 6.1% for temperature of thermal processing 75°C and reached 24.4% with increasing the temperature to 95°C. Thermal losses were mainly due to water and fat loss. These losses depend on the mass transfer process during thermal treatment, which in turn is influenced by the cooking procedure (i.e. final cooking temperature) and the composition of meat systems (i.e. moisture, fat and protein content). The amount of loss is probably related to the composition of muscle, denaturation of proteins by the ionic strength of the extracellular fluid. Denaturation is the change of protein structure during cooking which brings a decrease in diameter and thickness of the protein and so a less juicy and tougher cut [3, 6].
Table 3 shows some parameters of sensory evaluation of the model meat products. The temperature of thermal process had a strong impact on textural properties and eating quality of meat. Alongside with raising the temperature there were observed the increase of acceptability model meat products. The higher internal temperature was perceived to maximize the palatability characteristics (colour, aroma, flavour) of cooked meat.
Variable Parameters
Colour Aroma Flavour Saltiness Fragility Juiciness
A 5.1а 5.0a 5.0a 5.0a 5.0a 5.0a
B 5.2а 5.4a 5.4a 6.0b 7.0b 6.4b
C 6.6b 5.8a 6.6b 6.0b 7.0b 6.8b
D 6.2b 6.4b 6.8b 5.6b 7.8bc 5.4a
E 6.2b 6.8b 7.0bc 6.6c 7.6bc 7.2c
F 6.8 6.8b 7.0bc 6.6c 7.6bc 7.2c
G 7.0c 7.8c 6.8b 6.0b 7.2b 7.0bc
H 6.6bc 7.4bc 7.0c 6.8c 8.0c 7.0bc
I 6.2b 7.0bc 6.6b 6.6c 7.0b 5.6а
a, b, c - mean values denoted by various letters and placed in the columns are statistically significantly different at p < 0.05.
There were observed similar results for desirability of colour. The highest results of intensity and desirability of colour were obtained for sample G (7.0 points). Samples heated at 75°C were characterized by lower score. Differences of aroma intensity for the investigated samples were statistically significant. The highest notes for intensity and desirability of aroma were noticed also in sample "G" (7.8 points). Meat products under investigation were characterized great inconstancy also in flavour assessment. The highest scores of flavour evaluation were obtained for sample H and the lowest for reference sample A and sample B. There were statistically significant differences between results of saltiness, fragility and juiciness of meat products. Average value 8.0 points (sample H) for fragility desirability of investigated products was one of the highest evaluated sensory parameters. The most of model meat products were classified above 6.0 points for intensity of saltiness. Average value of juiciness was 7.0 points. Samples heated at 85°C with addition oil emulsion to brine solution obtained the highest notes for saltiness (7.2 points). There was no effect of oil content in the processed meat products on their juiciness. Conclusions
The results of this research indicate that increased cooking temperature results in lower WHC and cook loss and higher pH and dry matter. Addition of vegetable oil was not effecting in improving quality parameters of final products. Addition of vegetable oil did not improve significantly sensory quality of meat products under investigation.
References / Список литературы
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3. Joo S.T., Kauffman R.G., Kim B.C., Park G.B., 1999. The relationship of sarcoplasmic and myofibrillar protein solubility too colour and water-holding capacity in porcine longissimus muscle. Meat Sci. 52 291-297.
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5. Verbeken D., NeirinckN., Van Der Meeren P., Dewettinck K., 2005. Influence of к-carrageenan on the thermal gelation of salt-soluble meat proteins. Meat Sci. 70. 161-166.
6. Westphalen A.D., Briggs J.L., Lonergan S.M., 2005. Influence of pH on rheological properties of porcine myofibrillar protein during heat induced gelation. Meat Sci. 70. 293-299.
