国外“无麸质”食品的管理

为了规范\"无麸质\"(gluten free)食品标识,国际食品法典委员会、欧盟、美国、加拿大以及阿根廷等国相继发布了无麸质食品的相关法规或标准,定义了无麸质食品,提出了无麸质食品的质量控制、标注以及检测等方面的要求,并提出了管理及发展我国\"无麸质\"食品产业的对策。     

Influence of industrial sterilisation,freezing and steam cooking on antioxidant properties of green peas and string beans

We found that peptides or amino acids constituted the main fractions of water‐soluble nitrogenous compounds in green peas and string beans (44% and 79%, respectively). Their proportion increased after processing, especially in frozen peas and beans (61% and 95%, respectively). The content of phenolic compounds was decreased more after industrial processing (by 40% in peas and 50–70% in beans) than after cooking (by 20% in peas and 0–35% in beans). Antiradical activity against ABTS^?+ (2,2′‐azino‐bis[3‐ethylbenzothiazoline‐6‐sulphonic acid]) was much higher in aqueous extracts of peas and beans (33 and 45 μmol Trolox g^?1 d.m., respectively) than in aqueous acetone extracts (approximately 17 μmol Trolox g^?1 d.m. in both). In most cases, the activity decreased after processing. Both aqueous and acetone extracts of peas showed equal activity against DPPH^? (2,2′‐diphenyl‐1‐picrylhydrazyl), whereas in the case of beans this activity was four times lower in aqueous than in acetone extracts. Both reductions and increases of these activities were noted after processing.     

Preparation of novel distinct highly aromatic liquors using fruit distillates

This work describes the preparation of aromatised liquors using deodorised and concentrated fruit distillates. The raw spirits were improved by making a partial deodorisation, using activated charcoal, followed by concentration, using a distiller. The liquors were prepared by a maceration process. The procedure is exemplified using fig distillates to prepare myrtle berry liquors. The acidity, copper, polyphenol and anthocyanin indexes and volatile and anthocyanin profiles were monitored in each preparation step. The concentration process increased the ethanol proof to 75% v/v and decreased the acidity and the copper content. The partial deodorisation decreased the levels of high molecular weight volatiles, while the content of lower molecular weight compounds that contribute to flavour was maintained. Delphinidin‐3‐O‐glucoside, cyanidin‐3‐O‐glucoside, petunidin‐3‐O‐glucoside and malvidin‐3‐O‐glucoside were the major anthocyanins.     

食品中多酚形态的研究进展

近年来,植物多酚因其存在的普遍性、对食品品质形成的重要性以及众多的生理活性,已成为食品科学和营养学研究的一个热点。多酚以游离态和结合态两种形态存在于食品中。大量研究表明,植物多酚对食品品质及健康功能的贡献,不仅取决于其种类和数量,而且取决于其在食品基质中的存在形态。本文在广泛调研文献的基础上,对食品中多酚形态,不同形态多酚的分析方法,常见食品（谷物、水果、蔬菜、可食花卉、其他食品）中游离态多酚与结合态多酚的含量,以及食品加工对多酚形态的影响进行总结,并对食品中多酚形态研究存在的问题及其发展方向进行阐述。     

酸面团发酵技术在无麸质食物中的应用

无麸质食物是为乳糜泻人群应对麸质蛋白过敏而生产的一类食物,但无麸质食物因麸质蛋白的缺失,多存在口感差、体积小和硬度大等缺点。酸面团是一种传统发酵技术,通过酸面团中微生物的代谢作用,可产生蛋白酶降解麸质蛋白,同时还能提高无麸质食物的整体品质,如改善制品风味、提高营养价值、延长货架期等。本文主要对酸面团发酵技术及其在无麸质食物中的应用优势进行探讨,以期为无麸质食物研究提供理论参考。     

Solubility of a cruciferin‐rich protein product purified from rapeseed pressed cake (Brassica napus L.) by an aqueous processing method

Pressed cake from rapeseed (Brassica napus L.) is a promising plant protein source not yet utilised for human consumption due to the presence of antinutrients such as glucosinolates. Protein solubility is a crucial parameter influencing the functionality and thereby the applicability of proteins as food ingredients. A novel cruciferin‐rich rapeseed protein product was produced by an aqueous processing method in pilot plant scale. Intact glucosinolates were conserved by this procedure and largely removed from the protein products. Protein solubility in this product was examined when dispersed in 50 mm phosphate buffer, pH 8.0 with varying NaCl concentration (0–500 mm ). Unexpectedly, a salting‐out effect was observed of the globulin proteins, as 15.9 ± 0.6% protein was in solution at 500 mm added NaCl, whereas 21.5 ± 1.1% was solubilised without added NaCl; whether the observed effects originates from lipid and fibre constituents in the product remains to be resolved.     

Quality factors and grades for the classification and standardisation of complex ready pasta meals

The aim of this study is to arrive at a new classification of ready pasta meals, through the evaluation of their global quality, since their growing number, present in the market, often may be cause of confusion to consumers, because the parameters that contribute to the quality level are not clearly identifiable and measurable. After having explored several possible quality factors, we arrived at the conclusion that at least five must be taken into consideration: degree of pulping of the pasta, capacity to hold the sauce, weight constancy, wholeness and defects. Then, three quality grades are here proposed and discussed. Particular emphasis should be given to the sauce, because it highly influences on the global quality of these foodstuffs.     

Mathematical modelling of moisture sorption isotherms and determination of isosteric heat of blueberry variety O'Neil

The sorption isotherms of blueberry variety O'Neil were determined at 20, 40 and 60 °C, for a range of water activity of 0.10–0.95. The isotherms showed that the equilibrium moisture content increased when temperature decreased at constant water activity. The BET, GAB, Halsey, Henderson, Caurie, Smith, Oswin and Iglesias-Chirife equations were tested for modelling the sorption isotherms. The results showed that GAB, BET and Halsey models gave the best fit quality for the experimental desorption data, and BET, Oswin and Henderson for adsorption data as suggested by the statistical tests employed. The net sorption heat was calculated using the Clausius–Clapeyron equation giving 38.62 kJ mol⁻¹ (desorption) and 30.88 kJ mol⁻¹ (adsorption) at a moisture content of 0.01 g water (g d.m.⁻¹). Tsami equation was applied to estimate the net isosteric heat of sorption as function of equilibrium moisture content with satisfactory results.     

Bacterial biofilms in food processing environments: a review of recent developments in chemical and biological control

Biofilms are immobile communities of micro‐organisms attached to any surface, such as stainless steel or a food matrix surface or on packaging material. They may be composed of a single species, but more generally, in the natural environment, they consist of mixed species together with an extracellular matrix. Biofilms provide a common mechanism of persistence for a number of bacterial species especially in food processing environments, and therefore, prevention of biofilm formation and the removal of preformed biofilms are an important issue for the food industry. This article reviews the current understanding on the formation of biofilms and recent developments in biological and chemical methods for prevention and removal.     

微波处理对鲜湿面片褐变及其特性的影响

该研究探讨了微波处理小麦粉对鲜湿面片褐变及其特性的影响。利用微波技术处理小麦粉,测定鲜湿面片的色泽、小麦粉多酚氧化酶（Polyphenol Oxidase,PPO）活性,并通过分析面片水分分布、游离多酚含量、流变学特性以及小麦粉中蛋白质二级结构、巯基和二硫键变化,从而研究微波处理对鲜湿面片褐变及其特性的影响。研究结果表明：随着微波时间和功率的增加,鲜湿面片的白度呈现上升的趋势,在低微波功率下色泽无显著性差异,在较高功率700 W,处理时间为100 s时白度会因糊化现象而下降;PPO活性下降了42.78%,游离多酚24 h内变化量与未处理组比较下降了54.78%;面片弛豫时间T22和T23呈现先上升后降低的趋势,在中等强度处理时达到最大值;游离巯基整体呈现下降趋势,二硫键含量增加,在700 W处理100 s时分别为1.29、4.38 μmol/g;蛋白质二级结构中α-螺旋含量显著性下降,无规则卷曲含量显著性增加;在鲜湿面片的流变学特性中,G′和G″均呈现先增大后减小的趋势,tanδ呈现先减小后增大的趋势。综上所述,在微波功率为700 W,处理时间为80 s效果最佳,该研究可为面制品行业提供一定理论基础。