The potential allergenicity of novel foods

Recombinant DNA technology provides a powerful tool to create new products in many different fields. Agriculture and the agro-food industry are two of them. Genetic engineering aims at improving the yield, the nutritional quality or the technological value of food crops. The composition of foods may also be modified in order to decrease the content of toxic substances sometimes present in certain food crops. The expression of recombinant proteins in foods must be carefully assessed as proteins may induce allergic reactions in humans. Currently, the potential allergenicity of a protein can be reasonably assessed only when the protein is known to trigger an immune response in sensitive subjects. By contrast, the potential allergenicity of a protein of unknown allergenicity cannot be easily predicted as no immunoserum of allergic subjects is available. That is why an allergenicity assessment model for any genetically engineered food should be designed. Even though the gene product is completely characterised in the transgenic product, this does not necessarily provide information on its potential allergenicity. Animal models, in vitro tests and protein structure should be taken into account. Besides, allergenicity is a biosafety issue, for it deals with human health. The issue of food allergies in food safety should not be neglected, as an allergic reaction can be life threatening. ©1997 SCI     

转基因食品的致敏性评估

为推动中国转基因食品安全性评价工作，通过回顾转基因食品致教性评估策略的发展，重点介绍2001年FA0／wH0生物技术食品致教性联合专家咨询会议推荐的转基因食品致敏性树状评估策略，并对目前国内外关于转基因食品致敏性评估的不同方法进行了论述。     

How physical cues surrounding foods influence snack consumption: The case of covering foods

Physical cues surrounding foods are known to influence consumption, but research into the underlying mechanisms is limited. This research aims to disentangle these underlying mechanisms, testing one specific physical aspect: the presence or absence of a cover on snack bowls. We hypothesized that the presence (versus the absence) of a cover would decrease the likelihood of consumption and that the effect would be explained through a) norm perceptions discouraging eating, b) heightened effort to take the foods, and c) lowered salience of attractive foods. In two field contexts (Study 1, 40 observation periods; Study 2, N = 711) and a lab experiment (Study 3, N = 151), the cover’s presence was manipulated and the number of snacks taken was observed. In Studies 2 and 3, perceptions of social norms, effort, and salience were reported. The likelihood of taking snacks indeed decreased when the cover was present versus absent (Studies 1–3). In Study 2, the presence (versus the absence) of the cover seemed to decrease perceived social norms (p = 0.05) and increased perceived effort, whereas in Study 3 a significant decrease in perceived social norms and salience and an increase in perceived effort were observed. Moreover, the effect of the cover on likelihood of consumption was mediated by perceptions of salience. The organization of physical aspects in food environments influences consumption and may change perceptions of social norms, effort, and salience. Particularly, perceptions of salience might explain the effect of the cover on likelihood of consumption.     

Assessment of allergic potential of (novel) foods

In safety assessment of Novel Foods such as functional foods, allergy is a special issue on which particular emphasis has been placed. The reason for such concern is that incidence of food allergies is constantly and rapidly increasing. The severity of the reported incidents and the number of foods incriminated are also on the rise. The outstanding challenge is to understand what makes a common innocuous protein or peptide behave as an allergen for some groups of people, or why it may suddenly or progressively become a much more potent allergen than usual. It is therefore necessary to consider the risks of creating or unmasking new immunoreactive structures, or of overexposure to already reactive substances, as a result of new food-production and processing technologies. No test such as the use of animal models, the analysis of structure, function and physico-chemical properties is as yet available to evaluate or predict the allergenicity of a “novel” protein in a wholly reliable and objective manner. No indication has yet suggested that novel foods, and particularly recombinant proteins or genetically modified foods, would be more (or less) allergenic than the corresponding conventional foods. No particular structure can be described as being solely and intrinsically allergenic. The predictive approaches to determining the allergenic potential of NFs should therefore be subject to case-by-case critical appraisal allied to mandatory implementation of monitoring of the potential postmarketing impact of these new foodstuffs on public health.     

淀粉玻璃化转变及其对食品品质影响

淀粉是以谷物为原料的食品主要成分,而淀粉玻璃化转变对食品品质,特别对质构具有显著影响。该文在有关玻璃态和玻璃化转变理论基础上,综述淀粉玻璃化转变分析方法、影响因素及其对食品品质影响,并对今后研究方向进行展望。     

The influence of eating location on the acceptability of identically prepared foods

Three different classes of variables, namely the food, individual and situation, contribute to the appreciation of food. A dish, Chicken à la King and Rice, prepared from identical ingredients and to a standard recipe, was served to consumers in a variety of settings ranging from a residential home for the elderly to a 4-star restaurant. Local custom and procedures for the service and consumption of the dish were observed and diners asked to rate its acceptability. Results show that location contributed significantly (P<0.009) to overall acceptability. A hierarchy of locations emerge with upscale restaurants receiving higher scores than institutional settings. Gender did not appear to contribute to the variance although, in general, younger people tended to give lower ratings.     

Preliminary analysis and potential uses of date pits in foods

Date pits were examined for extractable high value-added components for including in functional foods. The objectives of this research were to conduct preliminary analysis of the pits from three leading varieties in UAE and to identify potential uses in foods. Date pits were odourless and had light to dark brown colour and a bland taste with slight bitterness. They contained 7.1–10.3% moisture, 5.0–6.3% protein; 9.9–13.5% fat; 46–51% acid detergent fibre; 65–69% neutral detergent fibre; and 1.0–1.8% ash. More than half of the pit protein could not be extracted consecutively with NaCl, ethanol and acetic acid. Pits had a substantial amount of oil that needed to be characterized for constituent components, biological activities and stability. Pits contained large quantities of fibre and, possibly, resistant starch that may have potential health benefits. Further research is needed to characterize isolated components and search for bioactive constituents with antimicrobial, antioxidant and other health-promoting activities.     

The potential of electrospraying for hydrophobic film coating on foods

There is a continuous need for thinner edible coatings with excellent barrier properties, and this requires new application methods. Electrospraying is known to yield fine droplets of size down to 20 μm, giving the potential of very thin and even coatings. A single electrospraying nozzle was used to characterise droplet formation and investigate the formation of thin films on well-defined surfaces. The experimental droplet size was successfully described as a function of operational parameters and liquid properties using scaling relations. The influence of operating parameters as nozzle height and electrostatic potential were evaluated as well.Thin film deposition was experimentally investigated for sunflower oil electro-sprayed on a highly conductive (aluminium) and insulating target surface (Parafilm). For both aluminium foil and Parafilm the droplet deposition was found to be random. For aluminium foil, being a conductive target, this was expected as repellence between droplets on the surface and new droplets is low, due to charge leakage to the ground. For Parafilm, droplet repellence appeared so large that droplets deposited on larger empty spots or were even pushed away from the surface. To evaluate the film formation performance, Monte Carlo simulations were carried out, and it was found that the method is a useful tool to characterise droplet deposition and film formation characteristics.     

Apple pomace as a potential ingredient for the development of new functional foods

Extruded snacks and baked scones were formulated with increasing levels (0–30%) of apple pomace (AP). The incorporation of up to 20% of AP in extruded snacks and in baked scones does not change significantly (P < 0.05) the proximate composition of the final products, except for the content of starch of baked scones. At this level of incorporation, the fibre content, phenolic content and antioxidant capacity (DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP) and β‐carotene/linoleic acid system) increased when compared to the products to which no AP was added. Chlorogenic acid and quercetin were the major phenolic compounds found in the products. Loss of phenolic compounds during heat treatment occurred; however, the DPPH radical scavenging activity of final products was not affected.     

Rheology of dairy foods that gel, stretch, and fracture

Casein gels are found in hard and soft dairy foods such as cheese and yogurt, and their rheological properties can be analyzed with various instrumental techniques. Empirical tests of cheese have been used since cheese making began, and imitative tests have been conducted in laboratories since the 1930s. Texture profile analysis is now the most frequently used imitative test. Fundamental tests provide a better representation of cheese and yogurt rheology because of the systematic mathematical treatment involved. Uniaxial compression and stress and strain relaxation tests are among the fundamental tests performed on cheese, and viscosity data are often used to investigate the physical characteristics of yogurt. Small amplitude oscillatory shear measurements are applicable to both products. Food scientists can acquire a clearer picture of the structure of dairy foods by performing appropriate rheological studies of the casein matrix.     

转基因食品潜在致敏性评价方法的研究进展

随着转基因食品在人类消费生活中的应用日益增加,人们对于完善转基因食品潜在致敏性评价方法的需求也不断增强.本文就现有转基因食品潜在致敏性的评价方法,包括决策树、序列同源性、血清学筛选、消化稳定性(抗胃蛋白酶性)以及动物模型等的研究进展做一概述,对其现状做出总结并对其发展提出建议.     

The influence of recent tasting experience on expected liking for foods

Expected liking is an important determinant of food choice and there is some suggestion that liking expectations are stable over time. Here we examine the impact that a recent ‘disappointing’ hedonic experience has on expected liking. In Study 1, we examine if a disappointing experience results in changes to expected liking one day after tasting and one week after tasting. In Study 2, we examine whether past frequency of eating a food determines whether a disappointing hedonic experience results in changes to expected liking. In Study 1, expected liking for a food was reduced 1 day after a disappointing experience, but not 1 week afterwards. In Study 2, past frequency of eating moderated whether expected liking for a food was reduced 1 week after a disappointing experience: expected liking of a infrequently eaten food was reduced, but not expected liking of a frequently eaten food. Liking expectations can be influenced by disconfirmatory hedonic experiences with a food product, but these effects are dependent upon the recency of the experience and the past frequency with which the food is eaten.     

Bromophenol formation as a potential cause of `disinfectant' taint in foods

A potential cause of `disinfectant' taints in foods is the formation of bromophenols as a result of reactions between brominating agents (residual or nascent) and phenol (food-derived or contaminating). This was studied using simple model systems containing either elemental bromine or bromochlorodimethylhydantoin (BCDMH) and phenol. Bromophenols were quantified by adding an internal standard to the model system and then analysing the compounds by solid phase micro-extraction and GC–MS. Low levels of bromophenols were generally formed in bromine mixtures, though this depended on the presence of citrate buffer and on storage of the bromine in the buffer prior to reaction with phenol. The individual bromophenol isomers were often present in considerably greater amounts than the published taste threshold levels. This was particularly evident for 2-mono- and 2,6-dibromophenol which were therefore the most likely causes of the `disinfectant' aroma in the simple models. The BCDMH reaction with phenol led to the same bromophenol isomers as in the elemental bromine reaction. Although bromophenol levels were lower, the taste thresholds for the 2-mono-and 2,6-dibromophenol were again significantly exceeded. The relevance of these observations for taint formation in foods is discussed.     

The influence of country-of-origin stereotypes on consumer responses to food safety scandals: The case of the horsemeat adulteration

Food safety scandals are recurring events in the food industry worldwide and companies are not immune to these incidents. However, there is a paucity of studies that examine how consumers evaluate and respond to brands involved in food crises and how consumers’ prejudicial views about brands may bias these responses. Following attribution theory, the current study analyzes the psychological mechanisms through which consumers form judgments about a brand’s culpability in the aftermath of a food safety scandal. Furthermore, this study assesses how the dimensions of a brand’s country-of-origin (perceived competence and perceived warmth) affect the mechanism of blame attribution.A real food crisis, the 2013 European horsemeat adulteration scandal, provides the framework for an experimental study with 816 Italian consumers. The results show that perceived country-of-origin warmth diminishes consumers’ perceptions of internal locus, stability, and controllability of the food incident, thus decreasing consumers’ attributions of blame toward the faulty brand. Perceived competence increases consumers’ perceptions of the controllability of the harmful behavior which leads to higher attributions of blame. Higher blame attribution leads to lower intentions to buy the brand in the future. Furthermore, when consumers perceive the food scandal as highly severe and when they are highly ethnocentric, perceived competence diminishes consumers’ perceptions of internal locus and stability of the food incident.The theoretical contribution of the study and practical implications for food brand managers are addressed.     

影响腐乳结晶物产生的因素

以青方腐乳为主要研究对象,分析了不同后酵时间段有结晶物青方腐乳样品相关指标的差异,并进行模拟实验,分析不同因素对结晶物产生的影响。结果表明:随着后酵时间的延长,腐乳卤汤中氨氮浓度持续增加,磷含量呈现先增加后减少的趋势,镁含量呈持续降低趋势,腐乳卤汤pH值逐渐升高;pH对于磷酸铵镁生成有非常强的依存性,氨氮浓度对磷酸铵镁结晶生成的影响程度很大,盐含量和酒精含量对磷酸铵镁结晶反应影响不显著。得出的主要结论为:后酵过程中氨氮浓度增大可能是青方腐乳结晶物产生量大的主要原因;低盐含量和高酒精含量有利于磷酸铵镁结晶的生成。     

葡萄酒市场价的影响因素

为什么一瓶赤霞珠红葡萄酒价值6美元,而用同种葡萄制成的发酵汁却价值150美元。答案是多方面的,其中有科技方面的原因,也有市场运作方面的原因。如果你要做葡萄酒,第一步就是要购买葡萄。赤霞珠葡萄至少500美元/吨,而具有声誉的那帕谷葡萄园生产的葡萄却要10,000美元/吨。1吨葡萄大约可生产700瓶葡萄酒,因此平均每瓶葡萄酒中葡萄成本就占到71美分～14美元。如果一个酒厂拥有自己的葡萄园的话,酒价会比较低,但是这对于一个本来就资金紧张的企业来说,这将是一笔巨额的资金投入。除去土地的最初成本,根据灌溉方式和架式的不同,种植葡萄树所用费…     

Plant foods in the management of Diabetes mellitus: Vegetables as potential hypoglycaemic agents

Vegetables are among the numerous plant adjuncts tried for the treatment of diabetes mellitus. A few vegetables that are commonly consumed in India have been claimed to possess antidiabetic potency. In recent years, there has been a renewed interest to screen such plant food materials, for a possible beneficial use. Considerable amount of work has been carried out in this regard with bitter gourd (Momordica charantia) and ivy gourd (Coccinia indica) both in experimental animals and human diabetic subjects. Majority of these studies have documented the beneficial effect of the fruit of bitter gourd and leaf of ivy gourd when administered orally as a single dose. The hypoglycaemic influence is claimed to be mediated through an insulin secretagogue effect or through an influence on enzymes involved in glucose metabolism. The limited number of studies on other vegetables such as cabbage (Brassica oleracia), green leafy vegetables, beans and tubers have shown the beneficial hypoglycaemic influence in both experimental animals and humans. There is scope for more extensive research in this area, especially to examine the long term beneficial effect of dietary vegetables, to identify the active principle, and to understand the mechanism of action, which is at present unclear. Since diet forms the mainstay in the management of diabetes mellitus, there is scope for exploiting the anti-diabetic potency of vegetables to the maximum extent. Such plant food adjuncts possessing hypoglycaemic activity appear to hold promise as potential antidiabetic agents.     

Pulse-based snacks as functional foods: Processing challenges and biological potential

Despite their high nutritional value and potential health benefits, pulse intake has not increased in the last three decades. Several strategies have been implemented to increase pulse consumption, such as their incorporation in bakery products, breakfast cereals, and snacks. The inclusion of pulses in these products could be an alternative to satisfy the consumers’ demand for healthy foods. However, pulse-based snacks face important challenges, including reducing antinutritional factors, achieving consumer acceptance, and consolidating the pulse-based snacks as functional foods. This review summarizes and discusses methods for producing snacks where cereals or tubers were replaced with at least 50% pulses. Also, it briefly assesses their effect on nutritional composition, antinutritional factors, sensory acceptance, and different health benefits evaluations. Extruded snacks exhibited high protein and dietary fiber and low fat content, contrary to the high fat content of deep fat–fried snacks. Meanwhile, baked snacks presented moderate concentrations of protein, dietary fiber, and lipids. Pulses must be pretreated using process combinations such as soaking, dehulling, cooking, fermentation, germination, and extrusion to reduce the antinutritional factors. Pulse-based snacks show good sensory acceptance. However, sensory evaluation should be more rigorous using additional untrained judges. Several studies have evaluated the health benefits of pulse-based snacks. More research is needed to validate scientifically the health benefits associated with their consumption. Pulse-based snacks could be an alternative to improve the nutritional composition of commercially available snacks. The use of pulses as ingredients of healthier snacks represents an important alternative for the food industry due to their low cost, sensory characteristics, high nutritional profile, and environmental benefits.