制备低苯丙氨酸特膳食品的研究进展

低苯丙氨酸特膳食品是苯丙酮尿症患者日常饮食所需的食品,但目前仍存在苯丙氨酸不达标、大多人工合成、安全性不足等问题,因此制备低苯丙氨酸特膳食品备受关注。本文就蛋白原料的筛选、蛋白中苯丙氨酸的游离、苯丙氨酸的吸附、特膳食品的开发等方面进行综述,重点围绕苯丙氨酸充分游离与高效脱除进行分析,同时指出目前该研究领域中存在的酶制剂特异性不足、吸附剂专一性不够等问题,并对未来的研究重点进行展望,以期为低苯丙氨酸特膳食品的制备研究及其产品研发提供参考。     

响应面试验优化红松松仁膳食纤维制备工艺及其理化性质分析

以红松松仁粕为原料制备松仁膳食纤维,利用响应面法优化制备工艺条件,并对其相关性质进行分析。通过比较筛选碱性蛋白酶为最适酶,选择pH值、加酶量、酶解温度、酶解时间4 个影响因素,在单因素试验基础上通过响应面试验设计,得到最优酶解工艺条件,并对此条件下得到的膳食纤维性质进行分析。结果表明：制备膳食纤维最优工艺条件为pH 9.2、碱性蛋白酶加酶量10 148 U/g、酶解温度50 ℃、酶解时间3.1 h,膳食纤维含量可达77.67%。相对于松仁粕,其持水力、膨胀力、持油力分别提高了24.17%、25.95%、40.44%,溶解性降低了63.94%。松仁粕经酶解后得到的膳食纤维具有较好的性能,对于实际应用具有重要意义。     

纤维素膜固定化麦麸酯酶的工艺研究

以麦麸中的植物酯酶为酶源,通过交联、吸附方法比较,选择物理吸附法将其固定于玻璃纤维素膜上,以酶活回收率为指标,探索其固定化的最佳条件。在单因素试验的基础上,利用Box-Behnken试验,进一步研究了缓冲液pH值、固定化时间、固定化温度3个因素及交互作用对麦麸酯酶固定化效果的影响,确定最佳固定化条件为:磷酸盐缓冲液pH值7.0,固定化时间4h,固定化温度29℃,该条件下酶活回收率的预测值为28.21%,验证值为27.51%。该研究为利用固定化麦麸酯酶快速检测有机磷和氨基甲酸酯类农药残留提供了技术参考。     

Development of a Drinkable,Peanut‐Based Dietary Supplement and Comparison of Its Nutritional and Microbiological Qualities with Commercial Products

This study was undertaken to formulate, using peanuts as a major ingredient, a beverage which will benefit older adults who are at a high risk of protein‐energy malnutrition and other health complications, and to compare its nutritional and microbiological qualities to commercial products. Peanuts, rice flour, and flaxseed meal in a ratio of 48.0:49.8:2.2 were mixed with water (20% solids) and cooked into gruel which was sequentially treated with BAN^®, (480 KNU‐B/g, 75 °C 1 h), Alcalase^® (2.4 AU‐A/g, 60 °C 1 h), and Flavourzyme^® (1000 LAPU/g, 55 °C 1 h) to predigest starch and protein, respectively. The degree of hydrolysis and product viscosity during hydrolysis was measured. The nutritional and microbiological qualities of the product were compared to 10 commercial products. Results indicate that 60% of starch was hydrolyzed while a total of 1.62% protein hydrolysis was observed. Product viscosity reduced from 228.55 to 3.60 cP at the end of hydrolysis. The formulation had no cholesterol and low sodium which was a functional property that was absent in the commercial products. Results of this study suggest that the formulation can be further optimized into a unique product that could cater for the protein needs and other nutritional requirements of older adults.     

碳纤维增强复合材料低温冷风磨削试验研究

采用SD80N100B金刚石砂轮开展了单向碳纤维复合材料的低温冷风磨削与常温干式磨削的对比试验研究,探讨了低温冷风与磨削参数对碳纤维复合材料磨削性能的影响。采用扫描电镜与超景深电子显微镜观察了磨削后的表面形貌和亚表面损伤情况,并分析了表面粗糙度的影响规律。试验结果表明：与常温干式磨削相比,低温冷风磨削的磨削力增大,表面粗糙度减小;在低温冷风和常温干式两种磨削方式下,纵向90°磨削较其他磨削方向的磨削力更大,表面粗糙度更小。     

Food Allergens: Is There a Correlation between Stability to Digestion and Allergenicity?

Food allergy is a major health problem in the Western countries, affecting 3–8% of the population. It has not yet been established what makes a dietary protein a food allergen. Several characteristics have been proposed to be shared by food allergens. One of these is resistance to digestion. This paper reviews data from digestibility studies on purified food allergens and evaluates the predictive value of digestibility tests on the allergenic potential. We point out that food allergens do not necessarily resist digestion. We discuss how the choice of in vitro digestibility assay condition and the method used for detection of residual intact protein as well as fragments hereof may greatly influence the outcome as well as the interpretation of results. The finding that digests from food allergens may retain allergenicity, stresses the importance of using immunological assays for evaluating the allergenic potential of food allergen digestion products. Studies assessing the allergenicity of digestion products, by either IgE-binding, elicitation or sensitizing capacity, shows that digestion may abolish, decrease, have no effect, or even increase the allergenicity of food allergens. Therefore, the predictive value of the pepsin resistance test for assessing the allergenic potential of novel proteins can be questioned.     

Nutritional,Health, and Technological Functionality of Lupin Flour Addition to Bread and Other Baked Products: Benefits and Challenges

Lupin is an undervalued legume despite its high protein and dietary fiber content and potential health benefits. This review focuses on the nutritional value, health benefits, and technological effects of incorporating lupin flour into wheat-based bread. Results of clinical studies suggest that consuming lupin compared to wheat bread and other baked products reduce chronic disease risk markers; possibly due to increased protein and dietary fiber and bioactive compounds. However, lupin protein allergy has also been recorded. Bread quality has been improved when 10% lupin flour is substituted for refined wheat flour; possibly due to lupin-wheat protein cross-linking assisting bread volume and the high water-binding capacity (WBC) of lupin fiber delaying staling. Above 10% substitution appears to reduce bread quality due to lupin proteins low elasticity and the high WBC of its dietary fiber interrupting gluten network development. Gaps in understanding of the role of lupin flour in bread quality include the optimal formulation and processing conditions to maximize lupin incorporation, role of protein cross-linking, antistaling functionality, and bioactivity of its γ-conglutin protein.     

Utilization of Food Processing By-products as Dietary,Functional, and Novel Fiber: A Review

Fast growing food processing industry in most countries across the world, generates huge quantity of by-products, including pomace, hull, husk, pods, peel, shells, seeds, stems, stalks, bran, washings, pulp refuse, press cakes, etc., which have less use and create considerable environmental pollution. With growing interest in health promoting functional foods, the demand of natural bioactives has increased and exploration for new sources is on the way. Many of the food processing industrial by-products are rich sources of dietary, functional, and novel fibers. These by-products can be directly (or after certain modifications for isolation or purification of fiber) used for the manufacture of various foods, i.e. bread, buns, cake, pasta, noodles, biscuit, ice creams, yogurts, cheese, beverages, milk shakes, instant breakfasts, ice tea, juices, sports drinks, wine, powdered drink, fermented milk products, meat products and meat analogues, synthetic meat, etc. A comprehensive literature survey has been carried on this topic to give an overview in the field dietary fiber from food by-products. In this article, the developments in the definition of fiber, fiber classification, potential sources of dietary fibers in food processing by-products, their uses, functional properties, caloric content, energy values and the labelling regulations have been discussed.     

大豆纤维稳定水包油型皮克林乳液的研究

近年来,由于食品级皮克林乳液在开发新型功能食品方面表现出潜在应用价值,关于食品级皮克林乳液的稳定剂的研究备受关注。本文主要研究了大豆纤维稳定玉米油的水包油型皮克林乳液的性质,通过测定ζ-电势、显微结构、乳液粒径变化、乳析指数、离心稳定性,分析了大豆纤维浓度(c;0.125%~1.0%,m/m)和油相质量分数(Φ;10%~40%,m/m)对乳液稳定性的影响。结果表明:Φ=10%时,随着大豆纤维的浓度增加乳液的粒径增大,絮凝程度增加,抗聚集稳定性和抗分层稳定性增强;c=0.75%时,随着油相质量分数增加乳液粒径显著增大,乳液稳定性迅速下降,且有明显油析现象出现。研究结果表明大豆纤维作为皮克林乳液的稳定颗粒有良好的潜力,对进一步深入研究大豆纤维稳定的皮克林乳液有指导意义。