Soy protein products in other foods

Both long-term and emerging patterns of utilization underscore the diversity of the use of soy protein products in processed foods other than meat foods. The purpose of this paper is to present a selective overview of this diverse usage.     

Soy proteins in foods—Retrospect and prospect

The soybean has been used for food in the Orient for centuries, but the western world has been slow to adopt it. In the last 40 years soybeans have become an important source of protein in poultry and livestock feed. In the last 10 years or so it has been used in foods in increasing amounts to supply low cost high quality protein with important functional properties. The soybean will be vital to meeting the protein needs of the future in all parts of the world, especially in the developing countries. The challenge is great to the plant breeders and agronomists to improve yields and adaptability of the crop and to the soy technologists to improve the characteristics of processed soybean proteins.     

Soy proteins for foods centering around soy sauce and tofu

In the Orient, soy proteins have been used for human consumption for centuries, during which various kinds of unique soy protein foods have been established. Some of these products, such as tofu, have a bland flavor, but there are also those products having a distinctive flavor and an aroma like fermented soy sauce. Both types are acceptable for worldwide populations. In earlier times, the consumption of these soy protein foods in the U.S. was mostly confined to Orientals. Recently, however, the koikuchi type of soy sauce has been consumed widely by non-Orientals through nationwide supermarkets. Annual production in the U.S. has reached more than 16,500 kl. Tofu has also become popular in the U.S. because of its bland flavor which enables it to be used in many dishes. Fermented soy sauce is completely different in the constituents of aroma and flavor from chemical soy sauce. Koikuchi shoyu is a typical Japanese type of fermented soy sauce characterized by a strong, appetizing aroma. The fermentation process consists of koji fermentation byAspergillus species and the subsequent brine fermentation, which contains lactic acid and alcoholic fermentations. Miso is a paste product produced through a similar fermentation. Tofu is a soy milk curd product made through a nonfermented process from soy milk.     

Soy protein foods in U.S. assistance programs

Soy protein food products occupy an important place in both U.S. overseas and domestic food assistance programs. In the overseas food donation program the products serve as the source of protein for the fortification of conventional processed commodities—wheat flour, corn meal, rolled oats, bulgur, and sorghum grits—and as a major source of protein in several cereal soy products designed for special use as child food supplements. Acceptance of these products has been good and more than 1 billion lb. of soy-fortified foods were distributed in the overseas program during July 1, 1972-June 30, 1973. In domestic food assistance programs, soy protein foods which meet U.S. Department of Agriculture requirements have been introduced into both school lunch and breakfast programs and also are distributed to needy families. Two products, textured soy protein and protein-fortified enriched macaroni, are permitted to meet part of the meat requirement in the Type A school lunch. In the school breakfast program, soy protein is a permitted ingredient in protein-fortified foods such as doughnuts, cake-like baked products, and cereal-fruit products. They were introduced primarily to meet the need for nutritious food items that require no kitchen facilities to prepare and are convenient to serve in schools that lack food service facilities. Specifications for the various food products are presented.     

Dietary glycemic index and the regulation of body weight

Prevalence rates of overweight and obesity have risen precipitously in the United States and other developed countries since the 1960s, despite comprehensive public health efforts to combat this problem. Although considerable attention has been focused on decreasing dietary fat and increasing physical activity level, the potential relevance of the dietary glycemic index to obesity treatment has received comparatively little scientific notice. This review examines how the glycemic and insulinemic responses to diet may affect body weight regulation, and argues for the potential utility of low glycemic index diets in the prevention and treatment of obesity and related complications. Revised from a paper originally published in the Proceedings of the Nutrition Society of Australia (Vol. 24, pp. 286–293) with permission of the Nutrition Society of Australia.     

Soy protein in foods: Their use and regulations in the U.S.

Soy proteins have been used at an ever increasing rate in various food systems because of their beneficial functional properties and low costs. Their use was limited because of taste, regulatory restrictions, and prejudice on the part of many. As technology advanced and as consumer needs changed, these limiting factors became less of a restriction. Flavor and functionability were improved through the introduction of new products or altered processing. The greatest change in regulatory attitude did not come about until after the White House Conference on Nutrition, when it was recommended that the consumer be given the advantages found in the new technologies that were being advanced. In making these changes, a number of new problems have been encountered. These problems, as well as the apparent trend in regulatory action, are discussed.     

Metabolic responses to high glycemic index and low glycemic index meals: a controlled crossover clinical trial

Background  

The consumption of low glycemic index (LGI) foods before exercise results in slower and more stable glycemic increases. Besides maintaining an adequate supply of energy during exercise, this response may favor an increase in fat oxidation in the postprandial period before the exercise compared to high glycemic index (HGI) foods. The majority of the studies that evaluated the effect of foods differing in glycemic index on substrate oxidation during the postprandial period before the exercise are acute studies in which a single meal is consumed right before the exercise. The purpose of this study was to investigate the effect of consuming two daily HGI or LGI meals for five consecutive days on substrate oxidation before the exercise and in the concentrations of glucose, insulin and free fatty acids before and during a high intensity exercise.     

Hexanal as a measure of rancidity in low fat foods

The concentration of n-hexanal in low fat, dehydrated foods can be determined in 10 min by the gas chromatographic analysis of the vapors from a 15 g sample suspended in boiling water. With 4-heptanone as an internal standard good day-to-day reproducibility was obtained and the results could be expressed as ppm hexanal in the sample. The onset of rancid odors was found to occur when the hexanal concentration increased to between 5 and 10 ppm. With an oat cereal good correlation between sensory evaluations and hexanal concentration between 0.3 and 5 ppm was obtained. The rate of hexanal increase at 55 and 45 C for a corn and a wheat cereal could be reliably projected to 37 and 21 C. Antioxidants applied to a wheat cereal reduced the rate of hexanal increase.     

Animal foods in traditional Australian aboriginal diets: Polyunsaturated and low in fat

Australian Aborigines develop high frequencies of diabetes and cardiovascular diseases when they make the transition to an urban lifestyle. The composition of the traditional diet, particularly its lipid components, is a most important aspect of the hunter-gatherer lifestyle that would bear on the risk of these diseases. We have examined the fat content and fatty acid composition of a variety of animal foods eaten traditionally by Aborigines from different regions of Australia. The muscle samples of the wild animals from all over Australia were uniformly low in fat (<2.6% wet weight) with a high proportion of polyunsaturated fatty acids (≥20% PUFA). Liver samples had a higher range of fat content (5–10% wet weight) but were also rich in PUFA (33–42%). Depot fat samples varied widely in their PUFA content (5–40%). In terms of their PUFA composition the foods tended to fall into three groups: (i) those rich in both n−3 and n−6 PUFA, which included land-based, coastal and freshwater animals; (ii) those rich in n−3 PUFA, i.e., marine species; (iii) those rich in n−6 PUFA, mainly land-based species. The results of these analyses suggest that even when the traditional Aboriginal diet contained a high proportion of animal foods it would have been low in fat with a high proportion of PUFA and thereby could have protected Aborigines against cardiovascular diseases and related conditions through a combination of factors: low energy density, low saturated fat and relatively high PUFA content.     

Endosperm and whole grain rye breads are characterized by low post-prandial insulin response and a beneficial blood glucose profile

Background  

Rye products have previously been shown to induce comparatively low post-prandial insulin responses; irrespectively of their glycaemic indices (GI). However, the mechanism behind this lowered insulin demand remains unknown. An improved insulin economy might contribute to the benefits seen in epidemiological studies with whole grain diets on metabolic risk factors and weight regulation. The objective of this study was to explore the mechanism for a reduced post-prandial insulin demand with rye products.     

Indices of insulin sensitivity and secretion from a standard liquid meal test in subjects with type 2 diabetes, impaired or normal fasting glucose

Background  

To provide an initial evaluation of insulin sensitivity and secretion indices derived from a standard liquid meal tolerance test protocol in subjects with normal (NFG), impaired fasting glucose (IFG) or type 2 diabetes mellitus.     

Comparison of a low carbohydrate and low fat diet for weight maintenance in overweight or obese adults enrolled in a clinical weight management program

Background  

Recent evidence suggests that a low carbohydrate (LC) diet may be equally or more effective for short-term weight loss than a traditional low fat (LF) diet; however, less is known about how they compare for weight maintenance. The purpose of this study was to compare body weight (BW) for participants in a clinical weight management program, consuming a LC or LF weight maintenance diet for 6 months following weight loss.     

Effects of body weight and alcohol consumption on insulin sensitivity

Background  

Obesity is a risk factor for the development of insulin resistance, which can eventually lead to type-2 diabetes. Alcohol consumption is a protective factor against insulin resistance, and thus protects against the development of type-2 diabetes. The mechanism by which alcohol protects against the development of type-2 diabetes is not well known. To determine the mechanism by which alcohol improves insulin sensitivity, we fed water or alcohol to lean, control, and obese mice. The aim of this study was to determine whether alcohol consumption and body weights affect overlapping metabolic pathways and to identify specific target genes that are regulated in these pathways.     

大豆中硼形态研究及豆制品中硼形态调查

文章以大豆为研究对象,建立微波辅助分步连续提取方法并应用于大豆及大豆制品中硼形态及分布的分析研究。按照该方法可将大豆中硼大致分为有机态硼和无机态硼,而无机态硼又可分为水溶性硼、络合态硼、沉淀态硼。其含量分布为:大豆总硼含量为36.15 mg/kg,无机态硼含量为30.66 mg/kg,占总硼含量的84.8%,有机态硼含量为5.49 mg/kg,占总硼含量的15.2%;无机态硼中水溶性硼占57.7%,络合态硼占29.4%,沉淀态无机硼占12.8%。对10种常见大豆制品中硼形态研究发现:豆豉的有机态硼含量高达82.7%,而其他非发酵性豆制品中无机态硼为主要的硼形态,占总硼比例的64.2%~98.6%,表明豆制品中硼形态与加工工艺有关。本研究可以为内源性硼及外源性硼鉴别提供一定的借鉴。     

Viscometric determination of the molecular weight of polymers in the low molecular weight region

In order to overcome the difficulty of the determination of the molecular weight of a polymer in the low molecular weight region by viscometry using the Mark–Houwink–Sakurada (MHS) equation, we have proposed the Dondos–Benoit relationship [η]^?1 = A₂ + AM^?1/2, for a number of polymer–solvent systems, for which we give the numerical values of the parameters A₁ and A₂. Furthermore, we suggest a method for the determination of the above parameters using the MHS constants a and k.     

Functionalization of low molecular weight atactic polypropylenePart II. Thermal and molecular weight studies

Summary Number average molecular weight (M_n), intrinsic viscosity ([η]) and glass transition temperature (T_g) of low molecular weight atactic polypropylene (APP) grafted with 4-allyl-1,2-dimethoxybenzene (DMAB), 4-allyl-2-methoxyphenol (eugenol) and 4-propenylanisole (trans-anethole) in the presence of dicumyl peroxide (DCP) at 170°C were determined. The influences of reaction time, concentration and extent of grafting on M_n, [η] and T_g of APP were examined. The data were discussed with the mechanism of grafting reactions. Received: 6 June 2000/Revised version: 23 July 2000/Accepted: 4 September 2000     

低分子量硫酸软骨素的制备及其性质研究

以过氧化氢+铜离子(Ⅱ)体系自由基法降解制备了低相对分子质量(简称分子量,下同)硫酸软骨素,并采用元素分析、红外光谱、原子力显微镜进行了结构表征和物化性质分析。结果表明,铜离子催化氧化降解后硫酸软骨素重均分子量从56 596降到6 906,己糖醛酸、氨基己糖及硫酸根等主要成分变化不大,差异不显著,降解前后热分解特性一致。原子力显微镜分析发现,降解前后硫酸软骨素在水中均以多股螺旋棒状形式存在,降解过程中,螺旋链部分断裂。结合红外光谱图,可以推测自由基引起的降解主要是造成硫酸软骨素二糖间β-1,4糖苷键断裂,而对β-1,3糖苷键无影响。     

Some properties of low molecular weight polybutadiene and polytetrahydrofuran

The proposition, that low molecular weight polymer fractions in good solvents behave as if they were under ? conditions, has been examined experimentally. Series of monodisperse hydroxy-terminated polytetrahydrofuran (PTHF), 82% 1,4-polybutadiene (PBD), and 30% 1,4-PBD were prepared, and values of M?_n obtained by vapor-pressure osmometry and endgroup analysis. The Mark–Houwink viscosity parameters K and ν were determined in a number of solvents. The general conclusion is that the proposition is invalid for these systems notwithstanding the fact that ν = 0.50 for one of them [82% 1,4-PBD in methyl ethyl ketone (MEK) at 25°C]. For this particular case, the following evidence suggests that these are actually ? conditions so that the apparent fulfilment of the proposition is fortuitous. (1) Cloud-point precipitation yields ? = 26 ± 3°C in MEK. (2) The value of K is close to that of K_? found elsewhere for PBD in a different solvent at a similar temperature. (3) Application of the Kurata-Stockmayer iterative procedure for estimating K_? from data in good and bad solvents yields a reasonably small discrepancy (10%) between the K_? values from data in toluene and MEK at 25°C for this polymer and only a 3% difference in the unperturbed dimensions (〈r₀²〉/M)^1/2 derived from them. Measured melting points T_m of PTHF (M?_n = 1000–13000), plotted as a function of chain length Z, viz., 1/T_m = 1/T_m0 + 2R/ZΔH_f, yield 43 ± 3°C and 1.6 kcal/submole, respectively, for the limiting melting point T_m0 and the heat of fusion ΔH_f. The former is in good agreement with the value obtained dilatometrically for high molecular weight polymer, while the latter indicates a degree of crystallinity of ca. 54%.