Thermal inactivation of trypsin inhibitors of soybean preparations added to meat

The activity of trypsin inhibitors was investigated in minced meat in which 30% of meat protein was replaced by soybean preparations (flakes, concentrate, isolate, textured flour). Trypsin inhibitors were determined in 20% suspensions of these soybean preparations. The activity of trypsin inhibitors in soybean preparations added to meat, or suspended in water, appeared to be higher than that of dry products. The heat treatment (70, 80, 90 and 100°C for 15 min) reduced the inhibitor activity in all soybean preparations, both in model meat systems (MMS) and in suspensions. Trypsin inhibitor activity was higher in MMS than in water suspensions of soybean preparations, suggesting that meat components protect trypsin inhibitor proteins against heat treatment. Trypsin inhibitor activity in heated meat model systems was too low to produce unfavourable nutritional effects.     

Easy determination of the addition of soybean proteins to heat-processed meat products prepared with turkey meat or pork-turkey meat blends that could also contain milk proteins

The addition of non-meat proteins to processed meat products is limited by regulations. Therefore, this work has investigated the determination of added soybean proteins in commercial heat-processed meat products prepared with turkey meat or pork-turkey meat blends that could also contain milk proteins. The method consisted of extracting proteins from the meat products in a Tris-HCl buffer (pH 8) and analysing the extract by high-performance liquid chromatography with a linear gradient water-acetonitrile containing 0.05% (v/v) TFA. This method enabled the detection and quantitation of up to 0.08 and 0.28% (w/w), respectively, of soybean proteins (related to 6 g initial product) in these products. Satisfactory precision and recovery data were established. Accuracy was evaluated by a comparison of soybean protein contents determined by the proposed method and the existing AOAC official method based on an enzyme-linked immunosorbent assay (ELISA) from which no statistically significant differences were observed.     

Relation Between Denaturation and Some Functional Properties of Soybean Protein

Selected functional properties of soybean protein heat denatured to different degrees were studied. Rheological properties (total breaking energy, Young's modulus) and water-holding capacity of soybean protein gel were improved by the preheat treatment applied during preparation of soybean protein. When soybean proteins were preheated in the presence of N-ethylmaleimide (NEM) or 2-mercaptoethanol (ME), the improvement in rheological properties was largely inhibited. But in the presence of potassium bromate (KB_rO₃), improvement in rheological properties occurred. The rheological properties and water-holding capacity of gel formed from ground meat containing NEM-treated soybean protein were similar to that of ground meat containing soybean protein preheated without NEM.     

The effect of phytic acid on oxidative stability of raw and cooked meat

The effects of phytic acid addition (0.1, 1 and 5 mM) to pork and beef homogenates on TBARS and metmyoglobin levels in raw meat, and TBARS and heme iron contents in cooked meat during 3 days of storage at 4 °C were investigated. Also, the role of inositol as a potential synergist of IP₆ (phytic acid) was examined. IP₆ effectively decreased the TBARS accumulation in raw and cooked meat homogenates. The metmyoglobin formation was inhibited in raw beef by phytic acid in a dose-dependent manner. The effect of IP₆ was more pronounced in cooked meat than in raw and in cooked beef homogenates more than pork. Inositol did not enhance antioxidant action of phytic acid in minced meat.     

Evaluation of salt, polyphosphates and their blends at different levels on physicochemical properties of buffalo meat and patties

The effects of sodium pyrophosphate (SPP), sodium tripolyphosphate (STPP), sodium hexametaphosphate (SHMP), sodium acid pyrophosphate (SAPP) and their blends at different levels (0·3, 0·5 and 0·7%), along with 2% sodium chloride on certain quality parameters of buffalo meat and patties were evaluated. The SPP, STPP and phosphate blends significantly increased pH, water-holding capacity (WHC), emulsifying capacity (EC), extractability of salt soluble proteins (SSP), colour of ground meat, decreased cooking loss (CL), improved emulsion stability (ES) and enhanced yield, texture and moisture retention of cooked patties. Compared to these phosphates, SAPP and SHMP had significantly poorer effects on improving the quality of meat and patties. The order of effectiveness of phosphates was SPP > STPP > SHMP. In general, pH, WHC, SSP, ES, yield and moisture content of patties increased progressively with increasing level of phosphate while CL decreased. Among blends containing two polyphosphates, those of 90% SPP + 10% SHMP and 75% SPP + 25% STPP were relatively more effective. A phosphate blend consisting of 65% SPP, 17·5% STPP and 17·5% SAPP was equally effective as that of SPP in improving the functionality of hot and chilled meat and had the advantage of reducing the amount of sodium by 3%.     

饲喂不同配比油脂饲料对肉鸡肉品质及肌肉中脂肪酸组成的影响

研究日粮中添加不同配比油脂对肉鸡肉品质、肌肉胆固醇含量及脂肪酸组成的影响。选取648只1日龄AA肉鸡,随机分成6组,CON为对照组(饲喂基础日粮),SO为正对照组(日粮中添加豆油),LO为负对照组(日粮中添加猪油),COP、COC、COV组分别在日粮中添加以棕榈油为主的配比油脂、以椰子油为主的配比油脂、多种植物油组成的配比油脂,实验期为42d。结果表明：COP组胸肌24h的滴水损失显著升高(P＜0.05);COC组腿肌烹饪损失显著降低(P＜0.05)。LO组胸肌不饱和脂肪酸/饱和脂肪酸得到提高(P＜0.05);SO、LO、COP、COC组n-3多不饱和脂肪酸含量均得到提高(P＜0.05);SO、COC组n-6多不饱和脂肪酸含量高于CON组(P＜0.05);除COV组外,各组n-6/n-3低于CON组(P＜0.05)。SO组胸肌胆固醇含量低于除LO组外的各组(P＜0.05)。结论：配比油脂组提高了肉鸡肌肉中多不饱和脂肪酸(PUFA)含量,对肉鸡肉品质没有产生不良的影响,豆油组改善了胸肌中脂肪酸比例并降低胆固醇含量,以椰子油为主的配比油脂次之。     

Determination of soybean proteins in commercial heat-processed meat products prepared with chicken,beef or complex mixtures of meats from different species

The addition of foreign proteins (mainly soybean proteins and milk proteins) to heat-processed meat products is a common practice. This work approaches the determination of additions of soybean proteins in heat-processed meat products prepared with chicken meat, beef meat, and complex mixtures of meats from different species (chicken, pork, beef, and turkey) by perfusion reversed-phase high-performance liquid chromatography. The applied method was previously developed for the determination of soybean proteins in pork and turkey meat products but it has never been tested for the determination of soybean proteins in other heat-processed meat products containing other kinds of meats. This paper demonstrates the validity of this method for the detection of soybean proteins in heat-processed meat products containing different varieties of meats and even in the presence of other foreign proteins such as milk proteins. The specificity and existence of matrix interferences have been checked for these samples and accuracy has been evaluated by the comparison of the soybean protein contents determined by the proposed method and the official ELISA method.     

Influence of sunflower flour on the extrusion behaviour of soya grits and the functional properties of the extrudates (Short communication)

Texturizing is the key to produce meat-like products from vegetable proteins; by application of texturized protein products it is possible to increase the substitution rate of meat in meat products, because such products have their own structure, and their addition will not cause such a structure loss as it is connected with addition of proteins as a powder. Thermoplastic extrusion is a relatively simple procedure to process flours to structurates [1, 2]. Our aim was to study the extrusion of mixtures of soybean and sunflower flours, because the amino acid compositions of the two proteins supplement each other.     

A PCR assay to detect trace amounts of soybean in meat sausages

Soybean proteins are the most widely used source vegetable proteins in the meat industry because of several interesting characteristics. As soybean is included in the group of ingredients potentially allergenic, if not declared, it can be considered a hidden allergen, representing a potential risk to sensitised individuals. The aim of this work was to optimise and apply DNA‐based techniques for soybean detection in meat products, as alternative to the currently used protein‐based methods. The optimised polymerase chain reaction (PCR) protocol targeting the soybean lectin gene enabled the detection of the addition of 0.1% and 0.5% of hydrated textured protein, which corresponded to 0.01% and 0.06% (w/w) of soybean protein in unprocessed and heat‐processed pork meats, respectively. The established PCR technique, when applied to commercial meat sausages (eighteen samples), confirmed the presence of soybean declared in nine samples and indicated the presence of soybean in four samples with no labelled information about soybean. Additionally, the event‐specific PCR detection of Roundup Ready^® soybean was also performed, enabling the detection of transgenic DNA in three samples.     

Sulfites in meat: Occurrence,activity, toxicity,regulation, and detection. A comprehensive review

Sulfites are a class of chemical compounds, SO₂ releasers, widely used as additives in food industry, due to their antimicrobial, color stabilizing, antibrowning, and antioxidant properties. As the results of these pleiotropic functions they can be added to a broad range of products including dried fruits and vegetables, seafood, juices, alcoholic and nonalcoholic beverage, and in few meat products. Sulfites ingestion has been correlated with several adverse and toxic reactions, such as hypersensitivity, allergic diseases, vitamin deficiency, and may lead to dysbiotic events of gut and oral microbiota. In many countries, these additives are closely regulated and in meat products the legislation restricts their usage. Several studies have been conducted to investigate the sulfites contents in meat and meat products, and many of them have revealed that some meat preparations represent one of the main sources of SO₂ exposure, especially in adults and young people. This review discusses properties, technological functions, regulation, and health implications of sulfites in meat‐based foods, and lays a special emphasis on the chemical mechanisms involved in their interactions with organic and inorganic meat components.     

乳酸钙处理对发芽大豆植酸降解和主要营养物质含量的影响

研究低浓度乳酸钙对大豆发芽过程中植酸降解以及主要营养物质含量的影响。在大豆发芽4?d期间,施用0.27?mmol/L乳酸钙喷淋对大豆植酸降解效果显著,并且提高锌、铁元素的生物利用率,利于人体对其吸收。此外,可溶性蛋白、可溶性糖含量不断下降,而游离氨基酸的含量随着可溶性蛋白含量下降而上升。总蛋白质含量与氨基酸总量基本保持稳定或略有下降,但氨基酸组成发生较大变化,在17?种氨基酸中,天冬氨酸和组氨酸含量随着发芽时间的延长而增加,其他氨基酸含量均呈下降趋势。乳酸钙处理条件下,促进了天冬氨酸和缬氨酸等氨基酸的累积和其他氨基酸含量的降低。乳酸钙作为优质钙元素补充剂,用低浓度喷淋处理可促进大豆发芽并大量降解抗营养因子植酸,提高营养品质。     

Salt, Phosphate and Oil Temperature Effects on Emulsion Capacity of Fresh or Frozen Meat and Sheep Tail Fat

The effects of K₂HP0₄, NaCl and oil temperature on emulsion capacity (EC) and microstructure of fresh and frozen Turkish beef was studied by utilizing a model system. EC of frozen meat was 6.4% higher than fresh meat. EC also increased with increasing phosphate levels increasing 8.5 and 10.4% over the control with 0.50 and 0.75% phosphate respectively. EC increased 1.6% for 3.0% salt over 2.5% salt. Microstructure photographs of the phosphate containing emulsions indicated the protein aggregates diminished and the emulsion was more homogeneous.     

Constitution of leguminous seeds. A note on protein-phytic acid interactions during isolation of acid-soluble protein from phaseolus beans

Acid-soluble proteins isolated from three types of Phaseolus beans (white kidney beans, navy beans and lima beans) were found to contain phytic acid. The amount of phytic acid complexed by the proteins was unaffected by the phytic acid content of the bean extracts from which the proteins were isolated but depended on the number of positively charged basic groups which were available for reaction with the phytate anion. It was found that the Neuberg formula for phytic acid (C₆H₂₄O₂₇P₆) represents more accurately the molecular formula of phytic acid associated with the isolated proteins, than does the Anderson formula (C₆H₁₈O₂₄P₆).     

Some Antinutritional Factors in Moringa peregrina (Al-Yassar or Al-Ban) and Soybean Products

Moringa peregrina and soybean defatted flours, protein concentrates, and isolates were assayed for trypsin (TIA) and α-amylase (AIA) inhibitor activities, phytic acid, tannin and chlorogenic acid contents, and in vitro protein digestibility (IVPD). TIA in M. peregrina defatted flour (MDF) was lower (P < 0.05) but more heat resistant than in soybean. AIA in MDF was lower than in soybean and inhibited pancreatic amylase more than bacterial amylase. Some M.peregrina products were higher in phytic acid but lower in chlorogenic acid than soybean. Tannin was low in all samples. IVPD was slightly lower for M.peregrina than for soybean.     

Functional Characteristics of Wiener-Type Products Substituted with Native and Acid-Hydrolyzed Oat Protein Isolates

Wiener-type products containing 5, 10 and 20% oat protein isolates (OPI), acid-hydrolyzed OPI or legume proteins were prepared and compared to an all-meat control. Cook yields progressively decreased with increases in the level of substitution, but there was no significant difference (p < 0.05) among samples containing the same amount of vegetable proteins. Wiener-type products containing acid-hydrolyzed OPI had significantly higher firmness and cohesiveness than those substituted with other vegetable proteins.     

Influence of the addition of mechanically recovered meat on the physico-chemical properties of meat model blends

The physico-chemical properties of meat model blends (basic composition: fresh lean pork, pork back fat, 2% NaCl, water with ice), with added mechanically recovered pork (MRM), were studied. Fresh MRM was added at levels of 10% and 20% substitution of meat protein with or without further substitution by 10% sodium caseinate or soya isolate. The addition of MRM to meat blends caused an increase in the pH, the water-holding capacity, the viscosity, the dominant wavelength and colour purity. No effects on emulsifying capacity were observed but thermal cooking losses and lightness of colour were reduced. The addition of blends of MRM and soya isolate or sodium caseinate caused lower values of the investigated features than those observed when only MRM was used.     

Frying oils with lower levels of saturated fatty acids induce less heterocyclic amine formation in meat floss (boiled,shredded and fried pork)

Heterocyclic amines (HAs) as potent mutagens are formed in meat floss which is a boiled, shredded and fried traditional meat product. In this study, effects of frying oils (lard, soybean oil and palm oil) on the formation of HAs in meat floss during frying have been investigated. The results showed that the contents of Norharman, Harman, AαC and MeAαC in meat floss that treated with lard and palm oil were higher than soybean oil which contained less saturated fatty acids (P < 0.05). The contents of total HAs in meat floss that treated with palm oil at 150 °C and 180 °C were significantly higher than that treated with soybean oil and lard (P < 0.05). In conclusion, meat floss treated with soybean oil at 120 °C, 150 °C and 180 °C contained lowest levels of HAs and soybean oil could be used as lard substitution to produce healthy meat floss.     

POST-MORTEM GL YCOL YSIS IN OX SKELETAL MUSCLE: EFFECT OF ADDING NICOTINAMIDE-ADENINE DINUCLEOTIDE TO DILUTED MINCE PREPARATIONS

ABSTRACT— Samples of mince, prepared from ox sternomandibularis muscle about 75 min postmortem, were diluted with one volume of 0.16M potassium chloride containing 0, 50 or 100 mM potassium phosphate with or without 1 mg of nicotinamide-adenine dinucleotide (NAD)/ml. Changes in pH and in the concentrations of glycolytic intermediates and the principal nucleotides were followed for about 6 hr after dilution. NAD was lost rapidly, its adenine moiety being converted to inosine nucleotide by the enzymes present. When the diluent did not contain inorganic phosphate (P_i) inclusion of NAD resulted in a somewhat faster loss of adenosine triphosphate (ATP), earlier cessation of glycolysis and higher ultimate pH. Inclusion of NAD in the preparations containing added P_i led to a reduction in both phosphorylase and phosphofructokinase activity. It also prevented the accumulation of fructose diphosphate. This was the result of lowering the phosphofructokinase activity rather than of increasing the glyceraldehyde-3-phosphate dehydrogenase activity. Adenosine triphosphatase (ATPase) activity, after an initial period during which it was unaffected by inclusion of NAD, was greater in the preparations containing added P_i and NAD than in the corresponding preparations without added NAD.     

Comparison of the Proteolytic Activities of New Commercially Available Bacterial and Fungal Proteases toward Meat Proteins

The hydrolytic activity of 3 commercially available protease preparations (bacterial protease G, fungal 31000, and fungal 60000) were examined using fluorescent‐labeled casein, azo dye‐impregnated collagen, and meat protein extracts from bovine M. semimembranosus and Achilles tendon, and compared to that of papain. Assays showed that all proteases exhibited little activity at low temperature (5 °C), and maximal activity at 45 °C. The pH, at which optimal activity was observed for each of the protease preparations, differed and ranged from pH 5.0 to 8.0. Kinetic parameters (K_M and V_max) were also different between protease preparations, with the bacterial protease G and papain exhibiting significantly higher V_max values (P < 0.001) and lower K_M values (P < 0.01) for the casein substrate than the 2 fungal protease preparations. Meat protein hydrolysis was displayed on SDS‐PAGE and proteins analyzed with mass spectrometry. The protease preparations were shown to have varying affinity toward different meat proteins. The bacterial protease G preparation was efficient at hydrolyzing most myofibril and collagen proteins, and appeared to be more efficient than papain at hydrolyzing collagen proteins. On the other hand the 2 fungal protease preparations showed a selective specificity toward meat myofibrillar proteins, and the fungal 60000 protease preparation exhibited high affinity toward collagen γ and collagen type I chain B proteins. The results generated in this study demonstrated that these commercial proteases have good potential for use in meat tenderization applications due to their mild and complementary effects on different meat proteins. Practical Application : Bacterial and fungal protease preparations exhibited varying affinities for hydrolyzing meat proteins. This selective moderate capability of microbial proteases compared to papain is potentially an advantage in avoiding over‐tenderization in meat. On the other hand, the bacterial protease G preparation, which appeared to be more efficient at hydrolyzing connective tissue proteins than papain, could be beneficial in tenderizing meat with high connective tissue content. The synergistic effect of these protease preparations could be incorporated into a meat tenderizing formula to give the tenderizer a broad activity spectrum, thus able to target different cuts of meat.     

Detection of allergenic additives in processed meat products

Allergic responses to food components are an increasing problem all over the world. It is therefore important to protect people who are vulnerable to food allergens against accidental and unintended consumption of products containing allergic ingredients. The meat industry commonly uses various allergic additives in the production of processed products, such as legumes (soy, peas, beans), milk and egg preparations, cereals containing gluten (wheat, rye, barley and oats), and spices (celery and mustard). These meat additives have specific technological properties, which help to create a texture or flavor profile, or affect the nutritional value, although some of them, such as soy, mustard, milk and egg white proteins, can cause severe allergic reactions. The aim of this paper is to discuss the application of various recently established methods of detection of allergenic additives in processed meat products – for instance cold cuts and sausages. The new methods are based mainly on protein, DNA, and isoflavones or phytic acid analysis. The article also characterizes the latest trends in the development of research on methods that would enable quick and reliable identification of targeted allergens in meat products. © 2018 Society of Chemical Industry