The influence of cooking and fat trimming on the actual nutrient intake from meat

The effects of cooking and trimming of visible fatty tissue on the content of fat, fatty acids, minerals and vitamins was studied in six meat cuts (beef rib-eye and brisket, pork neck steak and belly, veal chop and rolled breast) in order to improve the estimates of the actual nutrient intake from meat. Cooking decreased the absolute fat content by about 17.9-44.4% and therefore concomitantly influenced the content of different fatty acids. The trimming of visible fatty tissue additionally decreased the fat content by about 23.8-59.1%. Calcium, sodium, potassium, magnesium and phosphorus decreased during cooking in all cuts and cooking processes, while iron and zinc were found to increase in beef. All vitamins decreased during cooking, with thiamine showing the highest losses, from 73% up to 100%. In conclusion, the cooking and trimming of meat cuts considerably affected the nutrients in various ways and to different degrees, which should be taken into account when the nutrient intakes of meat are estimated.     

Effect of Thermal Treatment on Meat Proteins with Special Reference to Heterocyclic Aromatic Amines (HAAs)

Meat is one of the most imperative protein sources available with respect to its production and consumption. It is the richest source of some valuable nutrients like proteins, essential amino acids, polyunsaturated fatty acids, vitamins, and minerals like iron, zinc, and selenium. Thermal treatment produces conformational changes in protein structure as well as flavor, texture, and appearance, and chemical properties of the ingredients are also changed. Heterocyclic aromatic amines (HAAs), potent mutagens/carcinogens, are formed during the cooking of meat at high temperature. The review paper highlights the effects of various cooking methods, i.e., pan-frying, deep-frying, charcoal grilling, and roasting, on the formation of HAAs. The levels of HAAs produced in cooked meats vary depending upon the cooking method, time of cooking, and the type of meat being cooked. Metabolic behavior of HAAs is very unique, they interfere in the activity of many enzymes, modify the metabolic pathways, and lead to the adduct formation of DNA. The application of black pepper and several other spices during processing may reduce the formation of these (HAAs) mutagenic compounds.     

Effect of different cooking methods on vitamins,minerals and nutritional quality indices of orange-spotted grouper (<Emphasis Type="Italic">Epinephelus coioides</Emphasis>)

This study aimed to evaluate the nutritional value [proximate, fatty acid profiles, vitamins and minerals and also nutritional quality indices (NQI)] of orange-spotted grouper (Epinephelus coioides) prepared according to common consumer techniques: raw, poached, steamed, microwaved, pan-fried and deep-fried (in olive oil). There was an increase in protein, lipid and ash contents in cooked fish as compared to raw fish fillets. Cooking treatment had no significant effect on total n-3 fatty acids except for deep-fried fillets. Cooking methods had no significant effect on total n-6 fatty acids. In all the cooking methods, n-6 fatty acids were well preserved. There was no significant difference in the Mn, Zn, Ca and Fe contents of fillet between raw and cooked samples. Vitamin D content in all cooking methods did not differ significantly. None of cooking methods had a significant effect on vitamin A except for deep-frying fillets. However, vitamin B1 and B3 contents of cooked fish significantly decreased. Considering the overall nutritional quality indices, vitamin and mineral contents, steaming is the best cooking method.     

鱼香肉丝在烹饪前后营养成分的评价

为系统评价中国传统菜肴鱼香肉丝的营养品质以及烹饪前后的营养成分变化,将用于制作鱼香肉丝的原材料平均分成2组,每组3份,分别是生原料组和成品组。对其22种营养素指标进行检测,并分别对常规营养素、氨基酸、脂肪酸、矿质元素以及维生素进行营养评价。结果表明,在烹饪后鱼香肉丝的蛋白质显著升高(P<0.05),脂肪、磷、和铁的含量极显著升高(P<0.01),但氨基酸组成和脂肪酸总量无显著变化,维生素B₁显著降低(P<0.01)。蛋白质的氨基酸组成合理,必需氨基酸指数达到了85.91%;且多不饱和脂肪酸含量丰富,占总脂肪酸的58.36%。此外,矿质元素的营养质量指数均大于1(除钙以外),基本满足人体需求,但鱼香肉丝的维生素A和维生D含量较为缺乏,B族维生素(B₁、B₃、B₁₂)含量也低于中国居民膳食营养素摄入量的推荐值。综上,鱼香肉丝是一道营养丰富、均衡的菜肴,它具有优质的蛋白质、脂肪酸和丰富的矿质元素。烹饪会造成其维生素B₁的损失,而大大增加铁元素的含量,并且蛋白质和脂肪的含量会升高。本研究为膳食记录提供了更为准确的营养数据。     

Effect of Dietary Fiber on Properties and Acceptance of Meat Products: A Review

Meat is an important source of all essential nutritional components of our daily diet as it content most of the essential amino acids, fatty acids, vitamins, and minerals which are lack in plant based food, but it is devoid of dietary fiber, which is very essential component for normal physiological/biochemical process. During meat products processing, its functional values can be improved by supplementation of dietary fiber rich vegetative substances like cereal and pulse flour, vegetable and fruits pulp, etc. by this process, a significant proportion of required daily allowance of dietary fiber can be fulfilled for the frequent meat consumers. The consumption of meat products fortified with of dietary fiber can lead to the prevention of diseases like coronary heart disease, diabetes, irritable bowel disease, obesity, etc. On the other hand, the dietary fiber can effectively be incorporated in the processed meat products as binders, extender, and filler, they can significantly replace the unhealthy fat components from the products; increase acceptability by improving nutritional components, pH, water-holding capacity, emulsion stability, shear press value, sensory characters, etc. of finished products. Addition of dietary fiber in the meat products can increase the cooking yield therefore the economic gain as well.     

Nutritional value and digestion rate of rhea meat proteins in association with storage and cooking processes

The nutritional value of proteins was investigated after the storage and cooking of rhea M. Gastrocnemius pars interna. Oxidation of basic and aromatic amino acids, surface hydrophobicity and aggregation state of proteins, were determined in raw and cooked meat. In addition, myofibrillar proteins were exposed in vitro to proteases of the digestive tract. Cooking markedly affected the protein surface hydrophobicity. The BBP bound content was three times greater in cooked than in fresh rhea meat. A small increment in tryptophan content after cooking was observed. Storage influenced Schiff bases formation indicating the presence of protein-aldehyde adducts after cooking. High content of Schiff bases was found after cooking of samples stored for 5 days, demonstrating a probable implication of free amino groups, most likely from lysine. Cooking decreased the myofibrillar protein susceptibility to pepsin activity. After cooking, the proteolysis rate by pancreatic enzymes increased. Our findings support the importance of protein aggregation in the nutritional value of meat proteins.     

An overview of the nutritional value of beef and lamb meat from South America

The southern region of South America, a subtropical and temperate zone, is an important region for the production of beef and lamb meat, which is mainly produced in extensive pasture-based systems. Because of its content in highly valuable nutrients such as iron, zinc, selenium, fatty acids, and vitamins, meat is a unique and necessary food for the human diet in order to secure a long and healthy life, without nutritional deficiencies. Beef and lamb production systems based on temperate or tropical grasslands show interesting and, in some cases, a differential content in minerals, fatty acids and vitamins. This review deals with the distinctive aspects of the nutritional quality of beef and lamb meat produced in this region in terms of nutritional composition and the bioavailability of key nutrients related to its contribution for a healthy diet for all ages.     

Strategies to improve the nutritional value of meat products: incorporation of bioactive compounds,reduction or elimination of harmful components and alternative technologies

Meat is an excellent source of protein with a good balance of amino acids. It is also rich in several minerals, vitamins and bioactive compounds, which play important roles in metabolism and are easily assimilated from meat compared with other foods. The nutritional value of meat is one of the factors that influence consumer acceptance. However, it can be significantly reduced during processing. Moreover, some operations, such as curing, smoking or fermentation, used for processing can lead to the formation of harmful components in meat, and hence, nutritionists associate high consumption of processed meat with an increased risk of several diseases such as cardiovascular disorders and cancers. This review deals with the distinctive aspects of the technological strategies that can be used to improve the nutritional value of meat products, including the incorporation of bioactive components, reduction or elimination of harmful components (e.g. nitrite/nitrate, fat) and alternative technologies (ultrasound).     

Heterocyclic Aromatic Amines in Cooked Meat Products: Causes,Formation, Occurrence,and Risk Assessment

Meat products are sources of protein with high biological value and an essential source of other nutrients, such as vitamins and minerals. Heating processes cause food to become more appetizing with changes in texture, appearance, flavor, and chemical properties by the altering of protein structure and other ingredients. During heat treatment, heterocyclic aromatic amines (HAAs), potent mutagens/carcinogens, are formed due to the Maillard reaction. The HAAs are classified in at least 2 groups: thermic HAAs (100 to 300 °C) and pyrolytic HAAs (>300 °C). This review focuses on the parameters and precursors which affect the formation of HAAs: preparation, such as the marinating of meat, and cooking methods, including temperature, duration, and heat transfer, as well as levels of precursors. Additionally, factors are described subject to pH, and the type of meat and ingredients, such as added antioxidants, types of carbohydrates and amino acids, ions, fat, and other substances inhibiting or enhancing the formation of HAAs. An overview of the different analytical methods available is shown to determine the HAAs, including their preparation to clean up the sample prior to extraction. Epidemiological results and human daily intake of HAAs obtained from questionnaires show a relationship between the preference for very well‐done meat products with increased HAA levels and an enhanced risk of the incidence of cancer, besides other carcinogens in the diet. The metabolic pathway of HAAs is governed by the activity of several enzymes leading to the formation of DNA adducts or HAA excretion and genetic sensitivity of individuals to the impact of HAAs on human cancer risk.     

烹调加工对鱼类营养价值的影响

鱼是膳食中ω-3脂肪酸及多种维生素的良好来源,但这些营养成分经过烹调处理会受到不同程度的影响。本文综述了烧烤、油炸、微波、清蒸等烹调方法对鱼类ω-3脂肪酸及维生素保存率的影响,以及食用不同烹调处理的鱼对心血管疾病发生风险的影响,以指导合理烹调鱼类,使其充分实现营养价值。     

Designer eggs: from improvement of egg composition to functional food

Diet plays an important role in maintaining health. Among the different products delivering essential nutrients to the body, an egg has arguably a special place, being a rich and balanced source of essential amino and fatty acids as well some minerals and vitamins. This paper focuses on the benefits to the consumer of improving the nutritional quality of eggs by enhancing levels of anti-oxidants and n-3 fatty acids such as docosahexaenoic acid (DHA). The advantages of simultaneous enrichment of eggs with vitamin E, carotenoids, selenium and DHA include better stability of polyunsaturated fatty acids (PUFA) during egg storage and cooking, high availability of such nutrients as vitamin E and carotenoids, absence of off-taste and an improved anti-oxidant and n-3 status of people consuming these eggs. Having reviewed the relevant scientific literature it is concluded that “designer eggs” can be considered as a new type of functional food.     

Effect of sex, maturation stage and cooking methods on the nutritional quality and safety of black scabbard fish (Aphanopus carbo Lowe, 1839)

BACKGROUND: Black scabbard fish ( Aphanopus carbo Lowe, 1839) is a deep‐water fish resource that is highly appreciated in southern European countries and can accumulate high levels of mercury in the muscle. Currently, European legislation establishes limits for the presence of toxic contaminants in raw seafood, despite these products are generally cooked before consumption. In addition, there is still a lack of information concerning the nutritional quality and contaminants available in cooked products. Therefore, the aim of this study was to assess the effect of sex, maturation stages and three common cooking practices (steaming, grilling and frying) on the toxic elements (Hg, As, Cd and Pb) and nutritional value (chemical, elemental and fatty acid composition) of black scabbard fish. RESULTS: Few variations occurred between sexes and maturation stages, particularly in fatty acid and elemental content. Concerning cooked black scabbard fish, the greatest differences occurred in fried and grilled samples, attaining higher Hg levels, whereas steamed fish composition was closer to raw black scabbard fish. CONCLUSION: Raw and cooked black scabbard fish can be considered as a very good source of essential nutrients such as n‐3 PUFA, proteins, macro and trace elements. Yet, when the fish is grilled, the Hg content may be above the limits set by EU. Considering the alterations occurred during the cooking processes, steaming seems the best procedure to cook this species. Copyright © 2011 Society of Chemical Industry     

Proximate and fatty acid composition and cholesterol content of different cuts of guinea fowl meat as affected by cooking method

BACKGROUND: Poultry is one of the leading meat products in South Africa, and its nutritional composition can be affected by the cut and cooking method. Limited food composition data are available for typical South African poultry products. This study investigated the effect of different cuts and cooking methods on the proximate and fatty acid composition as well as the cholesterol content of guinea fowl (Numida meleagris) meat. RESULTS: The open‐roasting method produced the highest moisture content for all cuts, and the baking bag method the lowest. The baking bag method resulted in the highest protein content. Cooking method had no effect on fat content, although breast had the lowest and thigh the highest fat content. Ash content was highest in the open‐roasted drumstick. All cuts, regardless of cooking method, had a favourable polyunsaturated/saturated fatty acid (P/S) ratio (>0.4). Their n‐6/n‐3 ratio was also within the recommended beneficial range (<4:1). Both cooking method and cut affected cholesterol content. CONCLUSION: Different cuts of guinea fowl vary in proximate and fatty acid composition as well as in cholesterol content, which in turn is affected to varying degrees by cooking method. Copyright © 2012 Society of Chemical Industry     

肉制品中3类有害物质的来源与控制方法研究进展

肉制品中含有丰富的蛋白质、脂肪及糖类等物质,这些营养物质在特定加工条件下可发生相互作用,形成有害化合物,如烟熏过程中易于生成的多环芳烃、高温烹饪条件下易于生成的杂环胺以及添加亚硝酸盐作防腐剂时易于生成的N-亚硝基化合物等。本文综述以上3 类物质的危害性、形成途径、限量标准及相关控制方法的研究进展,以期为健康肉制品的开发提供理论参考。     

Meat fats in nutrition

This article reviews the fat content and fatty acid composition of meats in the human diet and discusses nutritional facts related to meat, meat products and other meat-containing foods as sources of dietary fats. Meat is an increasingly important source of high-value animal protein worldwide. Meat fat comprises mostly monounsaturated and saturated fatty acids, with oleic (C18:1), palmitic (C16:0), and stearic acid (C18:0) being the most ubiquitous. Meat and meat products are considerable sources of cholesterol in the diet. In most industrialized countries, a high meat intake contributes to a higher than recommended total and saturated fat and cholesterol intake. Another concern is that meat may replace sources of other important nutrients in the diet. Therefore, the advice to consumers is to prefer lean meats and low-fat meat products and use meat in moderation only.     

Cooking‐Induced Protein Modifications in Meat

Food ingredients commonly undergo heat treatment. Meat, in particular, is typically consumed after some form of heating, such as boiling or roasting. Heating of meat can introduce a wide range of structural changes in its proteinaceous components. At the 3‐dimensional structural level, meat proteins may denature and form aggregates upon heating. At the molecular level, primary structure (amino acid residue) alterations reported in cooked meat include protein carbonylation, modification of aromatic residues, and the formation of Maillard reaction products. Identification of these modifications is essential for determining the mechanism of thermal processing of meat and allowing better control of the nutritional and functional properties of products. This article reviews and summarizes the current state of understanding of protein modifications at the molecular level in commonly consumed mammalian food. In addition, relevant case studies relating to characterization of heat‐induced amino acid residue‐level modifications in other biological materials such as milk and wool are discussed to provide complementary insights.     

烹饪方式对马铃薯营养成分和生物活性物质影响的研究进展

马铃薯是全球重要的粮食作物,富含营养成分和生物活性物质。马铃薯通常采用煮、蒸、炸、烘焙等烹饪方式。在不同烹饪过程中马铃薯的物理、化学性质和酶活性的变化不同,从而影响马铃薯的营养成分和功能作用。本文综述了不同烹饪方式对马铃薯的营养成分及生物活性物质的影响,分析了烹饪方式对马铃薯抗氧化、抗癌症、调节血糖等功能影响的研究进展,以期为马铃薯的精深加工、综合利用提供参考依据。     

The effect of microwaves on nutrient value of foods

Microwave cooking has gained considerable importance as an energy‐saving, convenient, and time‐saving cooking method. This article reviews the state of the art of microwave cooking and the existing published data on the effects of microwave cooking on nutritive values of moisture, protein, carbohydrate, lipid, minerals, and vitamins. Most reports indicated that microwave cooking resulted in higher moisture losses compared with conventional methods. Overall, the nutritional effects of microwaves on protein, lipid, and minerals appear minimal. There is no report on the effects of microwaves on carbohydrate fraction in foods. A large amount of data is available on the effects of microwaves on vitamins. It is concluded that there are only slight differences between microwave and conventional cooking on vitamin retention in foods. In conclusion, no significant nutritional differences exist between foods prepared by conventional and microwave methods. Any differences reported in the literature are minimal.     

热处理对肉类蛋白特性及有害物质产生的影响研究进展

肉类是人类获取重要蛋白质的主要来源,而热处理是肉类食用前不可或缺的加工环节。在热处理过程中,一系列的生化反应基本从改变肉蛋白质的特性开始,不同的热处理技术在赋予肉类显著风味的同时也会引起蛋白质特性发生显著改变。在三维结构上,热处理后肉类蛋白可以变性并形成聚集体。在分子水平上,热处理改变了蛋白质的一级结构,影响了包括蛋白质羰基化、芳香残基的修饰和美拉德反应产物的形成。此外,热处理还会引起大量有害物的形成。因此,探究热处理后肉类蛋白特性及有害物产生是确定肉类加工机制和更好控制其产品营养和功能特性的关键。本文系统综述了肉类在经过不同热处理后的蛋白特性(变性、聚集和氧化)以及有害物质(杂环胺和多环芳烃)生成和减控的策略,以期为肉类加工企业、中央厨房以及家庭饮食中获得安全、健康的高质量肉类提供实用指南和理论基础。