香榧坚果中油脂和蛋白质的研究进展

香榧坚果营养物质丰富,是深受人们喜爱的名贵干果。近来从香榧坚果中发现多种生物活性成分,引起了从商者和研究者的广泛关注。本文综述了香榧坚果中油脂和蛋白质的研究现状,对香榧坚果脂肪酸的组成、油脂的研究内容及方法、油脂的功能特性及蛋白质进行了总结,并从油体蛋白的角度对香榧坚果中油脂和蛋白质的相互影响进行了简要讨论,以期为更好地开发利用香榧坚果资源提供方法和思路。     

Barcode High Resolution Melting analysis for forensic uses in nuts: A case study on allergenic hazelnuts (Corylus avellana)

Tree nuts are nutritionally important foods, being rich sources of vitamins, minerals, healthy fats and proteins and having cardio protective effects. Despite their healthy attributes, some tree nuts are also known for triggering adverse immune responses to individuals. Thus, an ongoing challenge in molecular biology is to develop rapid, accurate and reliable techniques to identify organisms and their processed foods, particularly those which could be contaminated with allergenic compounds. Lately, in addition to different chemical and immunological methods used, DNA based methods were also applied for this purpose. We describe here a novel, specific and highly sensitive High Resolution Melting analysis based method, using chloroplast barcoding regions (Bar-HRM) in order to a) obtain barcoding information for the major tree nut species (we have also included peanuts and sesame in our study) and b) to quantitatively identify one such allergenic tree nut species, like hazelnut in processed foods. The results show that the proposed method i) is capable of distinguishing among different tree nut species, ii) can be applied to processed tree nut products such as biscuits and iii) can detect a ratio of 0.01% of hazelnut in biscuits. In conclusion, it is demonstrated that BAR-HRM is suitable for the rapid, closed-tube and accurate screening of large numbers of tree nuts and/or of their processed foods and for the identification of allergenic tree nut species contained in processed foods.     

Prebiotic nut compounds and human microbiota

Nut consumption is clearly related to human health outcomes. Its beneficial effects have been mainly attributed to nut fatty acid profiles and content of vegetable protein, fiber, vitamins, minerals, phytosterols and phenolics. However, in this review we focus on the prebiotics properties in humans of the non-bioaccessible material of nuts (polymerized polyphenols and polysaccharides), which provides substrates for the human gut microbiota and on the formation of new bioactive metabolites and the absorption of that may partly explain the health benefits of nut consumption.     

Development and biological activities of marine-derived bioactive peptides: A review

Marine organisms are rich sources of structurally diverse bioactive compounds. Recently, a great deal of interest has been expressed regarding marine-derived bioactive peptides because of their numerous health beneficial effects. Moreover, many studies have reported that marine bioactive peptides can be used as antihypertensive, antioxidative, anticoagulant, and antimicrobial components in functional foods or nutraceuticals and pharmaceuticals due to their therapeutic potential in the treatment or prevention of diseases. This contribution presents an overview of the bioactive peptides derived from marine organisms and their biological activities with potential applications in different areas.     

Processing effects on tree nut allergens: A review

“Tree nut” is a broad term for classification of nuts that include cashews, almonds, hazelnuts, etc. Reports of mild to adverse immune reactions following the consumption of these nuts has been on a rise in recent years. Currently, about 1.2–2% of the world's population suffer from sensitivity to tree nuts. The only solution is complete abstinence from the allergy causing tree nut which is not feasible in most cases due to issues like cross contamination or their presence in the form of hidden ingredients in processed foods. Various studies have shown that food processing can effectively vary the secondary structures of the allergenic protein which in turn influences their functional properties. But, the impact of these processing methods on tree nuts allergens is mixed. This review gives an update on the recent findings on how conventional and novel processing methods influence the tree nut allergens.     

High-resolution Orbitrap™-based mass spectrometry for rapid detection of peanuts in nuts

Peanut represents one of the most harmful allergenic foods capable of triggering severe and sometimes lethal reactions in allergic consumers upon ingestion of even small amounts. Several proteins capable of inducing allergic reactions that have been recognised by patients’ IgE antibodies have been identified from this nut source. Methods mainly based on ELISA assays have been developed in order to detect peanuts in several food commodities. In addition LC-MS/MS methods based on different mass analysers have also been devised for tracing peanut contamination in different foods achieving low limits of detection. The applicability of a benchtop high-resolution Exactive? mass spectrometer has never been investigated for the rapid screening of peanut contamination in complex food matrices like mixtures of nuts. We report in this paper the design of suitable peanut markers and the development of an high-resolution Orbitrap? mass spectrometer-based method for peanut detection in a mixture of nuts species. With this aim, different types of samples were prepared: (1) nuts-based powder made up of a mixture of hazelnuts, pistachios, almonds and walnuts; and (2) nuts powder fortified with peanuts. Different levels of fortifications were produced and the applicability of the method was tested. Finally, a subset of six peptides fulfilling specific analytical requirements was chosen to check the suitability of the method tailored to the detection of peanuts in nuts-based products, and two of them, peptides VYD and WLG, were selected as quantitative markers. The method proved to be a suitable screening tool to assess the presence of traces of peanuts in other tree nuts with a limit of detection as low as 4 µg of peanuts proteins or 26 µg of peanuts in 1 g of matrix.     

利用纳米载体口服递送生物活性肽的研究进展

生物活性肽因具有高生理活性和生物相容性已被用于预防或治疗各种疾病。纳米载体在生物活性肽的稳定性方面发挥重要作用,对其穿过胃肠道时提供了强有力的保护作用。口服给药的方式往往会很大程度地降低生物活性肽的生物利用度,制备纳米颗粒作为生物活性肽的口服给药递送系统旨在提高生物活性肽的生物利用度,从而提高治疗的靶向性。因此,本文综述了生物活性肽口服纳米载体给药系统的研究现状,重点介绍了生物活性肽口服给药递送的条件、多功能给药递送系统及其应用,旨在为生物活性肽的最大化利用提供参考。     

Mycotoxins in edible tree nuts

Tree nuts (almonds, pistachios, and walnuts) are an exceptionally valuable crop, especially in California, with an aggregate value approaching $3.5 billion. Much of this economic value comes from overseas markets, with up to 60% of the crop being exported. The product can be contaminated with aflatoxins or ochratoxins, with the former being of special concern because of the strict regulatory levels (4 ppb total aflatoxins) applied by the European Community (EC). Natural, consumer-acceptable control methods are therefore required to conform to such limits. Research has shown that aflatoxin production is markedly decreased by the presence of natural antioxidants that occur in tree nuts, including hydrolysable tannins, flavonoids and phenolic acids. In vitro testing of individual compounds showed that the antiaflatoxigenic effect correlated with the structure and concentration of such compounds in individual nut varieties and species. This lead to the hypothesis that aflatoxin biosynthesis is stimulated by oxidative stress on the fungus and that compounds capable of relieving oxidative stress should therefore suppress or eliminate aflatoxin biosynthesis. Oxidative stress induced in A. flavus by addition of tert-butyl hydroperoxide to the media stimulated peak aflatoxin production and maintained high levels over time. However, aflatoxin formation was significantly inhibited by incorporation into the media of the antioxidant, tannic acid. Measures to increase natural products with antioxidant properties in tree nuts may thereby reduce or eliminate the ability of A. flavus to biosynthesize aflatoxins, thus ensuring levels at or below regulatory limits and maintaining export markets for U.S. tree nuts.     

Nuts, especially walnuts, have both antioxidant quantity and efficacy and exhibit significant potential health benefits

Free and total (after basic hydrolysis) polyphenols in nine types of raw and roasted nuts and two types of peanut butter (54 commercial samples) were analyzed after methanol extraction by a single step Folin-Ciocalteu reagent using catechin as standard. Walnuts had the highest free and total polyphenols in both the combined raw and roasted samples. Total polyphenols in the nuts were significantly higher than free polyphenols. Roasting had little effect on either free or total polyphenols in nuts. Raw and roasted walnuts had the highest total polyphenols. The efficacy of raw and roasted nut antioxidants was assessed by measuring the ability of the free polyphenol nut extracts to inhibit the oxidation of lower density lipoproteins (LDL + VLDL). A nut polyphenol, catechin, was measured after binding of three nut extracts to lower density lipoproteins. Walnut polyphenols had the best efficacy among the nuts and also the highest lipoprotein-bound antioxidant activity. Based on USDA availability data, the per capita total polyphenols was 162 mg from nuts per day in 2008. This corresponds to 19% of the total polyphenols from fruits and vegetables, nuts, grains, oils and spices in the US diet. Nuts provided 158 mg of polyphenols per day to the European Union diet. Nuts are high in polyphenol antioxidants which by binding to lipoproteins would inhibit oxidative processes that lead to atherosclerosis in vivo. In human supplementation studies nuts have been shown to improve the lipid profile, increase endothelial function and reduce inflammation, all without causing weight gain. These qualities make nuts a nutritious healthy snack and food additive.     

坚果中主要过敏原种类、检测及脱敏技术研究进展

近年来由于摄入坚果而导致的过敏反应屡见报道,已成为影响和威胁人体健康的一类重要的食品安全问题。本文对坚果中常见的过敏原的性质及危害进行了介绍,列举了目前国内外用于坚果过敏原检测的主要技术、特点及其应用,对比分析了不同处理方式对坚果中过敏原脱敏效果以及优缺点,指出目前坚果中过敏原检测及脱敏技术的不足和今后发展展望,旨在为坚果的加工和消费提供理论基础,助推坚果产业发展。     

自动点卤槟榔图像识别方法研究

针对机器对槟榔点卤出现漏点或者点空的情况,提出了一种基于H分量的图像分割方法来识别槟榔。将采集到的RGB彩色图像进行伽马增强再转换至HSV颜色空间,分离HSV颜色空间得H通道图像,再对H分量图像进行Otsu图像分割处理,结合图像形态学和区域生长法去除二值图像中出现的孔洞和小连通区域,最后通过绘制矩形框操作对识别出的槟榔进行标注。结果表明,该方法能完整地将槟榔从背景中分割出,且不会出现过度分割或者分割不足的问题。     

A New Frontier in Soy Bioactive Peptides that May Prevent Age‐related Chronic Diseases

During gastrointestinal digestion or food processing of proteins, small peptides can be released and may act as regulatory compounds with hormone‐like activities. Numerous biologically active peptides (bioactive peptides) have been identified. Most bioactive peptides are derived from milk and dairy products, with the most common being angiotensin converting enzyme inhibitory peptides. Soybean protein and soybean derived peptides also play an important role in soybean physiological activities, particularly those related to the prevention of chronic diseases. However, the bioactive potential of soybean derived bioactive peptides is yet to be fully appreciated. After a general introduction of approaches and advances in bioactive peptides from food sources, this review focuses on bioactive peptides derived from soybean proteins and their physiological properties. Technological approaches to generate bioactive peptides, their isolation, purification, characterization, and quantification, and further application in food and drug design are also presented. Safety concerns, such as potential toxicity, allergenicity, and sensory aspect of these peptides are likewise discussed.     

食用槟榔中苯并芘检测方法研究进展

综述了食用槟榔中苯并芘的污染来源以及检测食用槟榔中苯并芘的前处理方法,归纳了几种常用的检测食品中苯并芘的仪器分析方法,指出目前已有的苯并芘检测方法的不足之处,并对槟榔中苯并芘的检测方法的研究方向进行了展望。     

腰果过敏研究进展

腰果过敏是一种严重的树坚果过敏。近年来,随着腰果消费量迅速增长,腰果过敏发生率随之呈上升趋势,腰果正在成为一种重要的食物过敏原。少量的过敏原可导致严重的过敏反应,甚至危及性命。然而,目前腰果过敏显然是一个被严重低估的健康问题,尤其是对儿童。因此,社会迫切需要给予腰果过敏足够的重视,并有必要向公众广泛宣传腰果过敏的严重性。本文就腰果过敏的流行病学、过敏原成分、临床特点、诊断以及预防治疗等方面进行系统综述,旨在为腰果过敏的社会认识和深入研究提供科学信息。     

澳洲坚果仁营养成分分析与其加工副产物的综合利用研究

澳洲坚果香脆可口,营养丰富,富含多种人体生长所必需的营养物质,同时我国的澳洲坚果种植面积广。因此,该文重点对澳洲坚果仁的营养成分进行分析,并对澳洲坚果仁的加工副产物,包括澳洲坚果壳、澳洲坚果青皮以及澳洲坚果粕的综合利用进行综述,以期为澳洲坚果的市场化开发和综合利用提供理论参考。     

Brazil nuts and associated health benefits: A review

Epidemiological studies have shown an inverse relationship between nut intakes and chronic diseases such as cardiovascular diseases and cancers. The composition of lipids, minerals, and phytochemicals, and their associated health functions in Brazil nuts are critically reviewed. The nuts have high nutritive food value containing 60–70% oil and 17% protein. Brazil nuts contain abundant dietary antioxidants, especially selenium (Se). One single Brazil nut provides 160% of the US Recommended Daily Allowance (RDA) of selenium - perhaps the best source of Se from plant-based foods. Brazil nuts possess phenolics and flavonoids in both free and bound forms and are rich in tocopherol, phytosterols, and squalene. These compounds' possible beneficial effects are due to their antioxidant and antiproliferative activities, which are linked to a reduced risk for developing atherosclerosis and cancer.     

Walnuts and almonds as model systems of foods constituted by oxidisable,pro-oxidant and antioxidant factors

Walnuts and almonds were selected as complex model systems in order to study possible interactions among oxidisable substances, pro-oxidant species and antioxidants. Lipoxygenase activities in a direct-micelle system were determined for these nuts according their globulin contents in their soluble protein fraction. Walnut lipoxygenase activity was 1.5 times higher than that of almonds. Among antioxidant compounds, hydrophilic contents were analysed in these nuts, hence, extractable, hydrolysable and condensed phenolic compound fractions were determined as well as lipophilic phenolic concentration corresponding to tocopherol fraction. Extracts of brown skins and whole walnuts have significantly higher phenolic contents than those of almonds. Radical scavenging activities of phenolic extracts were measured. Besides, the experiments demonstrated the ability of all nut extracts to inhibit the coupled oxidation of linoleic acid with β-carotene induced by lipoxygenase. The antioxidant substances were mainly found in nut brown skins. Walnut extracts showed higher antioxidant activity than those of almonds. Lipoxygenase pro-oxidant activity was also measured in AOT reverse micelles in conditions that model these nuts.     

Electron beam radiation of dried fruits and nuts to reduce yeast and mold bioburden

Dried fruits and nuts make up a significant portion of the commodities traded globally, and the presence of yeasts and molds on dried fruits and nuts can be a public health risk because of the potential for exposure to toxigenic fungi. Since current postharvest treatment technologies are rather limited for dried fruits and nuts, electron beam (E-beam) radiation experiments were performed to determine the doses required to reduce the yeast and mold bioburden of raisins, walnuts, and dates. The indigenous yeast and mold bioburden on a select number of commodities sold at retail ranged from 10(2) to 10(3) CFU/g. E-beam inactivation kinetics based on the linear model suggest that the decimal reduction dose required to eliminate 90% of the microbial population (D10-value) of these indigenous fungal populations ranges from 1.09 to 1.59 kGy. Some samples, however, exhibited inactivation kinetics that were better modeled by a quadratic model. The results indicate that different commodities can contain molds and yeasts of varying resistance to ionizing radiation. It is thus essential for the dried fruit and nut industry to determine empirically the minimum E-beam dose that is capable of reducing or eliminating the bioburden of yeasts and molds in their specific commodities.     

基于混合模式色谱生物活性肽的分离研究进展

生物活性肽是一类具有生理活性的小分子蛋白类物质,对其进行高效分离纯化有助于进一步发挥其生物活性和研究其构效关系。然而目前活性肽分离步骤繁琐。鉴于此,研究者开发了混合模式色谱（mixed-mode chromatography,MMC）分离技术：同时利用活性肽在亲疏水、电荷特性等方面的性质差异,通过对固定相进行多重改性,并辅以不同流动相,在分离过程中MMC可发挥多重保留机制,从而实现对特定肽段的高效分离。MMC具有固定相可控、可特异性识别和分离效率高等优点。本文梳理和总结MMC固定相以及对生物活性肽的分离研究及应用现状,以期对活性肽的高效利用提供参考。     

Defining and characterizing the “nutty” attribute across food categories

The term “nutty” has been used to describe a vast array of foods including many foods outside the realm of nuts. However, it is not clear if “nutty” is a single term or if it takes various forms, depending on the type of product. The objective of this study was to determine whether a single nutty term could be used to describe nuttiness in all food products or if additional terms were needed. More than 200 products with potential nutty flavor, including nuts, nut spreads, grains/cereals, seeds, beans/legumes, oils, cheeses, fish, and beverages, were studied. Five “nutty” concepts were found and described with terms, definitions, and references with intensity ratings: overall nutty, nutty-beany, nutty-buttery, nutty-grain-like, and nutty-woody. Four of those attributes, excluding overall nutty, were single concept attributes that described subgroups of nuttiness. Specific terms, such as peanut or almond, that describe a certain type of nut but are separate from the “nutty” character were excluded intentionally because they do not describe nutty, they describe an overall concept flavor beyond nutty. A second panel of trained assessors was used to review the lexicon. This panel used this lexicon to describe a set of 10 products (nuts, grains, beans, seeds, cheeses) and determine if any additional attributes were needed to describe nuttiness. All of the products displayed varying intensities of the nutty attributes and the panel found no additional terms for the “nutty” component were needed. The development and verification of the lexicon has real-world application because it can assist in product development and quality assurance when describing foods with a “nutty” attribute. These terms can be applied across all food categories and is not exclusive to characterizing nuts.