食品抗氧剂的气相色谱分析

为了监控叔丁基对苯二酚的反应过程,提高收率和保证产品质量,探讨了用毛细管气相色谱分析产品的试验方法。测定了对苯二酚、叔丁基对苯二酚、2,5-二叔丁基对苯二酚的保留时间和相对校正因子,回收率分别为100.3%、98.2%和101.8%。     

天然产物抗氧化活性的常见评价方法

天然产物抗氧化活性的评价是天然产物研究的重要组成部分,对其在日化领域的开发应用具有显著的指导意义。本文从实验原理、实验方法等方面对天然产物抗氧化活性的常见评价方法进行综述,详细介绍了化学分析法中的自由基(ABTS自由基阳离子、DPPH自由基、超氧自由基、羟自由基)清除实验、脂质过氧化抑制实验、还原能力测定及脂质氧化抑制等评价方法;描述了以生物细胞为模型的CAA抗氧评价方法;概述了在动物体内进行的抗氧化活性评价方法及指标,为相关领域中抗氧化天然产物的研究和开发提供实验理论基础。     

Neutron activation analysis and its application to the analysis of food products

High-flux thermal-neutron activation analysis (NAA) is an extremely sensitive means of quantitatively determining most of the elements of the periodic system. The usual limits of detection, for 75 of the elements, in the absence of appreciable interferences, range from picograms (for some elements) to as high as micrograms (for less sensitive elements). A typical element can be determined down to as low as a nanogram. This high sensitivity enables one to analyze food products, for example, for numerous trace-level elements that may be present: whether natural or added beneficial essential trace elements, or deleterious elements introduced from pesticide residues (such as Br, As and Hg), or from processing (such as Cr, Sn, Sb and Cu). Studies to be reported include the nondestructive determination of Hg in foodstuffs down to levels as low as 0.01 ppm, and of Br in foodstuffs down to about 0.1 ppm. With radiochemical separations, these detection limits can both be extended to 0.001 ppm, if needed. By combination with paper chromatographic or solvent extraction techniques, phosphorus- and halogen-containing pesticides can be sensitively determined. The NAA method can also be used to advantage at element levels much higher than trace levels, and in such cases the very high neutron flux of a nuclear reactor may not be necessary. For example, even with a small 14 Mev neutron generator, the nitrogen content of foodstuffs can be determined nondestructively, rapidly and accurately, down to levels of about 100 ppm. These determinations can also be made on-line, in food processing plants. Presented at the AOCS-AACC Joint Meeting, Washington, D.C., April, 1968.     

Cottonseed protein food products

Upward trending world population and increasing costs for traditional food proteins provide many incentives for utilization of oilseed proteins directly in human diets. Cotton, as one of the world's major oilseed crops, represents a potential source of food protein. Acceptability of oilseed protein products in terms of functional properties in food systems and nutritional value will largely determine the extent of their utilization by the food industry. Liquid cyclone process cottonseed flour, defatted glandless cottonseed flour, storage protein isolates, and cottonseed whey proteins have been evaluated by various functionality tests and in a number of food systems. The cottonseed flours have been subjected to processing by extrusion texturization. Human feeding studies have also been conducted. Results indicate a good potential for use of cottonseed protein products in a variety of food systems.     

Wheat gluten applications in food products

Vital wheat gluten has traditionally been noted for its functional benefits in various bakery applications. In recent years extensive research and development work has taken place to more clearly identify wheat gluten’s unique characteristics and functional properties. As a result, many new and novel applications have been developed. The on-going potential of this exciting protein ingredient, in its native or modified forms, will only be limited by the imagination of those formulating new products.     

Stability of coconut oil in food products

The active oxygen method (AOM) stability of refined coconut oil is generally 250 hr; however, samples with as low a stability as 30 hr have been obtained. The addition of BHA, BHT and citrate increased the AOM stability to about 350 hr even though the initial stability was 30 or 250 hr. Refined coconut oil samples which hydrolyzed from 2 to 10 times as rapidly as normal oils have been encountered. Such samples are undesirable for food production as soapy off-flavors may be produced. The rate of hydrolysis of coconut oil samples was evaluated by a simple laboratory test. Coconut oil free fatty acids produced a soapy off-flavor at a lower level in sweet foods than in salty ones. Soapy off-flavors were produced in a low moisture food containing coconut oil by the lipase activity of cinnamon.     

A review of the antioxidant potential of medicinal plant species

Some researchers suggest that two-thirds of the world's plant species have medicinal value; in particular, many medicinal plants have great antioxidant potential. Antioxidants reduce the oxidative stress in cells and are therefore useful in the treatment of many human diseases, including cancer, cardiovascular diseases and inflammatory diseases. This paper reviews the antioxidant potential of extracts from the stems, roots, bark, leaves, fruits and seeds of several important medicinal species. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxylanisole (BHA) are currently used as food additives, and many plant species have similar antioxidant potentials as these synthetics. These species include Diospyros abyssinica, Pistacia lentiscus, Geranium sanguineum L., Sargentodoxa cuneata Rehd. Et Wils, Polyalthia cerasoides (Roxb.) Bedd, Crataeva nurvala Buch-Ham., Acacia auriculiformis A. Cunn, Teucrium polium L., Dracocephalum moldavica L., Urtica dioica L., Ficus microcarpa L. fil., Bidens pilosa Linn. Radiata, Leea indica, the Lamiaceae species, Uncaria tomentosa (Willd.) DC, Salvia officinalis L., Momordica Charantia L., Rheum ribes L., and Pelargonium endlicherianum. The literature reveals that these natural antioxidants represent a potentially side effect-free alternative to synthetic antioxidants in the food processing industry and for use in preventive medicine.     

Fatty acid profile in baby food products

The fatty acid composition in the lipid phase of 64 commercially available baby food products, of two different batches each, was analyzed. They comprised vegetable products for babies of five, eight, and twelve months and fruit and cereal products of three different brands. The comparison of the composition of the saturated (C18:0, C16:0, C14:0, C12:0, C10:0), the unsaturated monoenoic (C18:1n9 and C16:1n7) and the polyenoic (C18:2n6 and C18:3n3) fatty acids was determined by gas chromatography. All analyzed baby food products provided well‐balanced amounts of saturated fatty acids on the one hand (saturated fatty acids (SFA) 31—37% of total fatty acids) and unsaturated fatty acids on the other hand (monounsaturated fatty acids (MUFA) 23—26% and polyunsaturated fatty acids (PUFA) 38—46% of total fatty acids, respectively). The P/S‐ratio in vegetable products of five months reached a value of 1.5, in all other analyzed products it was around 1. The n‐6:n‐3‐ratio was 10:1 in fruit and cereal products, followed by 11.6:1 in vegetable products of eight and twelve months and 13.5:1 in the group of vegetable products of five months. Since there is a lack of arachidonic acid and docosahexaenoic acid in baby food products, it might be of advantage to consider whether such products should be supplemented by these long‐chain polyunsaturated fatty acids.     

Lipid oxidation in meat and meat products—A review

Lipid oxidation is a major cause of deterioration in the quality of meat and meat products. Oxidation can occur in either the stored triglycerides or the tissue phospholipids. Ferric heme pigments have been implicated as the major prooxidants in tissue lipid oxidation. Pigment and lipid oxidation are interrelated, and ferric hemes are believed to promote lipid oxidation. The resulting oxidation destroys the hemes. Nonheme iron and ascorbic acid may also function as prooxidants in meat. Sodium chloride accelerates oxidation of the triglycerides, although the mechanism of salt catalysis is not completely known. Cooked meat undergoes rapid deterioration due to tissue lipid oxidation. The meat pigment in the cured pink ferrous form does not promote the rapid oxidation undergone by cooked uncured meat. Refrigerated and frozen fresh meats are also susceptible to lipid oxidation. Protein denaturation and cross-linking may result from lipid oxidation in stored freeze-dried meat. With increased consumption of prepackaged raw meat and precooked convenience meat items, control of oxidation has become increasingly important. Antioxidants and chelating agents are the most effective inhibitors of lipid oxidation. One of 28 papers presented at the Symposium, “Metal-Catalyzed Lipid Oxidation,” ISF-AOCS World Congress, Chicago, September 1970.     

抗氧化剂在个人护理品中的研究进展

抗氧化剂被广泛应用于制药、功能化妆品等的生产、加工和贮藏过程中,其通过抑制生物机体活性氧簇的产生,或阻止其进一步链式氧化反应达到抗氧化目的.对目前抗氧化剂的种类及应用研究等进行了简单概述.分析抗氧化剂的未来发展方向,合成型抗氧化剂将逐步退出市场,天然提取型或以天然植物提取物为原料的衍生抗氧化剂由于无毒、绿色和低成本等优点,被消费者和生产企业所广泛青睐.     

Potential use of microcapsules in manufacture of fibrous products: A review

The present survey shows that microcapsules are used as effective tools for modification and functionalization of fibrous products. The core and shell materials of microcapsules can comprise various active ingredients in accordance with different requirements of final fibrous products. In this survey, the morphology, functional properties and added values of microcapsules, also such advanced types as nanocapsules, bi-, multifunctional microcapsules, and their applications in smart and other modern products are described. Some relevant applications of microcapsules in industrial processes are briefly discussed. The techniques used to encapsulate the core ingredients are also overviewed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47066.     

Synergistic effect of BSA on antioxidant activities in model food emulsions

Sunflower oil-in-water emulsions containing TBHQ, caffeic acid, epigallocatechin gallate (EGCG), or 6-hydroxy-2,5,7,8-tetramethylchroma-2-carboxylic acid (Trolox), both with and without BSA, were stored at 50 and 30°C. Oxidation of the oil was monitored by determination of the PV, conjugated diene content, and hexanal formation. Emulsions containing EGCG, caffeic acid, and, to a lesser extent, Trolox were much more stable during storage in the presence of BSA than in its absence even though BSA itself did not provide an antioxidant effect. BSA did not have a synergistic effect on the antioxidant activity of TBHQ. The BSA structure changed, with a considerable loss of fluorescent tryptophan groups during storage of solutions containing BSA and antioxidants, and a BSA-antioxidant adduct with radical-scavenging activity was formed. The highest radical-scavenging activity observed was for the isolated protein from a sample containing EGCG and BSA incubated at 30°C for 10 d. This fraction contained unchanged BSA as well as BSA-antioxidant adduct, but 95.7% of the initial fluorescence had been lost, showing that most of the BSA had been altered. It can be concluded that BSA exerts its synergistic effect with antioxidants because of formation of a protein-antioxidant adduct during storage, which is concentrated at the oil-water interface owing to the surface-active nature of the protein.     

Soy flour and grits for use in food products

Processing alternatives enable the soybean processor to manufacture soy flour products which vary in fat content, granulation and degree of heat treatment. By controlling these variables, the processor is able to regulate the nutritional value and functional properties of these products. The application of soy flour products is dependent upon their functional properties, nutritional value and low cost. Currently, the major markets for soy flour and grits are in pet foods and animal feeds, cereal based foods and ingredients, meat based foods, and as a substrate for refined protein products such as the textured vegetable proteins, soy protein concentrates, isolates and hydrolysates. These soy protein products are generally marketed as functional and nutritional substitutes for meat, milk and egg protein. For example, soy flour is a functional replacement for milk in many cereal-based foods, e.g., bread, and also enhances the nutritional value of the cereal protein by supplying lysine to the formulation. The United States government has pioneered the development and marketing of protein-enriched, cereal-based foods designed to combat worldwide starvation. The government has directly supported the research and development of corn and wheat-based food substrates supplemented with soy flour, and has purchased over one billion pounds of these products since 1966 for worldwide distribution. One of 21 papers presented at the Symposium, “Oilseed Processors Challenged by World Protein Need,” ISF-AOCS World Congress, Chicago, September 1970.     

Textured and shaped oilseed protein food products

The major emphasis in developing textured and shaped protein foods has been with the use of soy proteins. The availability at a low stable price, the high protein content and quality, and the inherent chemical properties of the protein allowing for unique structure development are major reasons for its strong world-wide use. The changing economic trends of many basic protein foods are creating a need for the use of unique textured proteins either as ingredients in existing foods or allowing improved functionality in new products. The two main procedures for texturing and shaping oilseed protein are spinning of protein isolates, and direct extrusion of flour. The spinning technique is more expensive and has greater product functionality in contrast to the direct extrusion method. Consumer acceptance is in large part correlated with the technological success of imparting desirable colors, flavors and textural properties in the finished food product. Examples of these variations are given. The use level of these textured proteins, particularly in meat products, are restricted by labeling standards. The present regulations are not clearly defined. Current proposals for labeling textured vegetable proteins when used with meat products involve standards on a ratio to meat basis. One of 21 papers presented at the Symposium, “Oilseed Processors Challenged by World Protein Need,” ISF-AOCS World Congress, Chicago, September 1970.     

A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef

Growing consumer interest in grass-fed beef products has raised a number of questions with regard to the perceived differences in nutritional quality between grass-fed and grain-fed cattle. Research spanning three decades suggests that grass-based diets can significantly improve the fatty acid (FA) composition and antioxidant content of beef, albeit with variable impacts on overall palatability. Grass-based diets have been shown to enhance total conjugated linoleic acid (CLA) (C18:2) isomers, trans vaccenic acid (TVA) (C18:1 t11), a precursor to CLA, and omega-3 (n-3) FAs on a g/g fat basis. While the overall concentration of total SFAs is not different between feeding regimens, grass-finished beef tends toward a higher proportion of cholesterol neutral stearic FA (C18:0), and less cholesterol-elevating SFAs such as myristic (C14:0) and palmitic (C16:0) FAs. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD) activity as compared to grain-fed contemporaries. Fat conscious consumers will also prefer the overall lower fat content of a grass-fed beef product. However, consumers should be aware that the differences in FA content will also give grass-fed beef a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef. In addition, the fat from grass-finished beef may have a yellowish appearance from the elevated carotenoid content (precursor to Vitamin A). It is also noted that grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through the consumption of higher fat grain-fed portions.