GC-MS分析灯笼果果汁和果酒的香气成分

香气决定水果和果酒的风味典型性。利用液液萃取及气相色谱和质谱联用技术（GC-MS）分析灯笼果果汁及果酒中的香气物质。结果表明,灯笼果果汁中检出22种香气物质,主要香气成分为亚油酸和苯乙烯;灯笼果果酒中共检测出37种香气物质,主要香气成分为苯乙醇、琥珀酸二乙酯、己二酸二(2-乙基己)酯、苹果酸乙酯和异戊醇。本研究数据可为灯笼果酿酒工艺改进提供参考。     

Metabolomic Profiling of Carotenoid Constituents in Physalis peruviana During Different Growth Stages by LC‐MS/MS Technology

With the current ongoing changes in global food demands, natural carotenoids are preferred by consumers and are gaining attention among food scientists and producers alike. Metabolomic profiling of carotenoid constituents in Physalis peruviana during distinct on‐tree growth stages was performed with liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) technology. The results show that the β rings of β‐carotene are hydroxylated with great efficiency, and there is a continual synthesis of zeaxanthin at half‐ripe and full‐ripe stages, which is confirmed by relating the zeaxanthin content to that of its precursor (β‐carotene). Lutein was, in terms of mass intensity, the most abundant carotenoid constituent (64.61 µg/g at the half‐ripe stage) observed in this study. In addition, γ‐carotene, which is rare in dietary fruits and vegetables, was detected in the mature and breaker stages, albeit at a relatively low level. The results suggest that when we consider the variation in carotenoid content during different growth stages, Physalis peruviana can be considered a good source of natural carotenoids.     

Ethephon‐induced fractional changes of pectic polysaccharides in developing cape gooseberry (Physalis peruviana L) fruits

Pectic polysaccharides extracted from fruit tissue of cape gooseberry (Physalis peruviana L) at different maturity levels were fractionated and analyzed for galacturonic acid backbone molecules. Preharvest spray of the fruits at 7 days old with ethephon resulted in a higher accumulation of water‐soluble and oxalate‐soluble pectic fractions than non‐treated fruits, while this treatment effectively enhanced the polygalacturonase enzyme activity necessary for maintenance of pectin degradation. Treatment with ethephon not only enhanced the solubilization rate but also resulted in a net increase in total pectic polymer content in developing cape gooseberry fruits. Copyright © 2005 Society of Chemical Industry     

Oil extractability from enzymatically treated goldenberry (Physalis peruviana L.) pomace: range of operational variables

Goldenberry pomace (seeds and skins) represents a large portion of the waste generated during juice processing (ca. 27.4% of fruit weight). The potential of goldenberry agro‐industrial wastes for use as raw material for production of edible oil was evaluated. Fruit pomace, contained 6.6% moisture, 17.8% protein, 3.10% ash, 28.7% crude fibre and 24.5% carbohydrates. The n‐hexane‐extractable oil content of the raw by‐products was estimated to be 19.3%. Aqueous enzymatic extraction was investigated for recovery of oil from the fruit pomace. The most significant factors affecting extraction were enzyme concentration, the time of digestion with enzymes, substrate concentration in water and the particle size of substrate. A broad variation in oil recovery was obtained depending on the operational conditions during the enzyme‐aided aqueous extraction. The optimum and economical values were those obtained for 4:0.02:1 water:enzyme:substrate ratio. Generally, enzymatic treatment increased the extraction yield. The more than 42% yield by enzymation compared with the nearly 3% yield in the control process (without enzyme) implies a significant increase in yield by about 92.8%. In single‐enzyme trials, cellulase EC gave the best yield. Although proteases slightly improve yield, the enhancement values are much lower than those obtained with Cellulase EC and Pektinace L40. Rapid increase in oil yield occurred as the enzyme concentration increased from 1 to 2 g/100 g substrate. Yield increased with dilution, but it began to fall when the substrate became more diluted. Moreover, extractability increased significantly when particle size reduced. Concerning the oil composition, there were no great changes in the fatty acid pattern of the oils extracted with different hydrolytic enzymes when compared with each other or to the solvent extracted oil. The main purpose of this study was to maximise the efficiency of the enzymatic treatment for oil recovery from goldenberry pomace. As a first step toward developing goldenberry as a commercial crop, the results provide important information for the industrial application of the fruit.     

Impact of enzymatic treatment on chemical composition,physicochemical properties and radical scavenging activity of goldenberry (Physalis peruviana L.) juice

Tropical pulpy juices play an important role in nutrition as an excellent base for low‐calorie and dietetic products. Goldenberry (Physalis peruviana L.) is one of the most promising exotic fruits and many interesting functional products could be developed from these berries. In this work we are reporting, for the first time, on the chemical composition and some physicochemical parameters of the goldenberry fruit juice. We have also investigated how some of these properties are affected by enzymatic treatment and pasteurisation. By enzymation, not only is the yield of juice increased, but also the macro‐ and micro‐components. Application of enzymes, moreover, leads to juices with higher pulp content, higher acidity and higher total soluble solids. On the other side, enzyme‐treated juices were characterised by lower alcohol‐soluble solids and pH values. Water‐ and fat‐soluble bioactives were estimated in appreciable amounts in the juice. The antioxidative potential of different processed juices was assessed by means of bleaching of the stable 1,1‐diphenyl‐2‐picrylhydrazyl radicals and the resulting values were correlated with each of the antioxidant compounds. The results obtained can be considered very satisfactory and the juice could be widely appreciated when compared with other products commonly available on the market. The data are helpful for the optimisation of goldenberry juice production. It was the purpose to present a comprehensive assessment of the goldenberry juice and to address the potential for its delivery in functional drinks. Copyright © 2006 Society of Chemical Industry     

毛酸浆开发利用的研究进展

毛酸浆营养丰富,具有降血压、预防动脉硬化和心血管疾病等活性,是一种极具开发价值的天然产物。综述了毛酸浆浆果的营养成分及其在食品工业中的应用,并对毛酸浆的应用前景予以展望,以期对毛酸浆的开发利用有促进作用。     

Use of phenolic compounds from olive mill wastewater as valuable ingredients for functional foods

ABSTRACT

Olive mill wastewater (OMW) is a pollutant by-product from the virgin olive oil production. Its high content in phenolic compounds makes them play an important role for their use in foods, for their high antioxidant significance. The present paper gives an overview on the techniques for OMW valuable ingredient separation, focusing on the most effective ones for their use in food products as functional ingredients. We report on effective methods to recover OMW phenolics, and give several examples on the use these extracts in foods. When added into vegetable oils, their effect on retarding lipid oxidation improves the oxidative status of the product, whilst several challenges need to be faced. OMW phenolic extracts were also used in food emulsions, milk products or other model systems, showing promising results and little or no negative impact on the sensory characteristics or other properties. Their possible use as antimicrobial agents is also another promising approach, as positive results were obtained when applied in meat products. Other examples of using natural phenolic extracts from other sources are suggested also for OMW extracts, to expand their use and thus to improve the nutritional and technological quality of foods.     

酸浆花萼色素的提取及理化性质研究

采用不同的试剂提取酸浆花萼的天然色素，并且对色素的理化性质进行研究。结果表明：该色素在丙酮中提取效果最好，其最大吸收峰在406nm处；色素在不同温度下稳定性良好：在不同食品添加剂条件下稳定性良好：在太阳光照条件下对色素有减色作用；色素有较明显的抑菌作用。     

Effect of different drying methods on drying characteristics,colour, total phenolic content and antioxidant capacity of Goldenberry (Physalis peruviana L.)

In this study, the effects of convective, microwave and microwave–convective drying methods on the drying characteristics, colour, total phenolic content and antioxidant capacity of goldenberry fruits were investigated. To select the most appropriate thin‐layer drying model for drying treatments, nine mathematical drying models were fitted to the experimental data. Based on the statistical tests used for evaluation, the Midilli et al. and Wang and Singh models were considered the best models to describe the drying behaviours of goldenberry fruits in all drying methods. The colour values (L*, a* and b*) of fresh fruit were decreased by drying. Compared with the fresh sample, the dried samples exhibited a 64–75% and 65–75% decrease in total phenolic content and antioxidant capacity, respectively. Among the different drying treatments, the values closest to those of fresh samples with respect to colour values, total phenolic content and antioxidant capacity were achieved with the 160 W microwave drying method.     

响应面法优化超声提取酸浆宿萼中叶黄素的工艺及抗氧化活性研究

对酸浆宿萼中叶黄素的提取工艺进行研究。以正己烷为溶剂,超声波辅助提取法,考察提取时间、超声功率和料液比对提取率的影响,采用响应面法对其进行优化。结果表明:最佳工艺为提取时间35min,超声功率430W,料液比1∶37,叶黄素的提取率为8.19%。酸浆宿萼中叶黄素提取物清除DPPH·和·OH的半抑制质量浓度IC50分别为0.2195mg/mL和0.4031mg/mL,抗氧化活性较高,可作为一种良好的天然抗氧化剂。该工艺可用于酸浆宿萼中叶黄素提取的工业生产。     

酸浆宿萼中酸浆苦素抑菌稳定性的研究

考察温度、pH值、可见光和紫外线对酸浆宿萼中提取的酸浆苦素抑菌特性的影响。通过对几种常见腐败菌和致病菌的抑菌性测定,结果表明：酸浆苦素对于革兰氏阳性菌的抑菌效果较明显,对部分霉菌有抑制效果,对酵母菌无抑菌效果。对于金黄色葡萄球菌的最小抑菌浓度（minimum inhibitory concentration,MIC）为31.3 μg/mL,对于霉菌中纯黄丝衣霉的MIC为62.5 μg/mL。pH值对酸浆苦素抑菌性影响较大,其次是温度,可见光和紫外线对其抑菌效果影响不明显。在20～35 ℃时抑菌活性最强,高温对其抑菌活力影响不大。酸浆苦素抑菌性在酸性、中性、弱碱性溶液中均较为稳定,而强碱性环境会迅速破坏其抑菌性能。     

Complexation of starch and phenolic compounds during food processing and impacts on the release of phenolic compounds

Phenolic compounds can form complexes with starch during food processing, which can modulate the release of phenolic compounds in the gastrointestinal tract and regulate the bioaccessibility of phenolic compounds. The starch–phenolic complexation is determined by the structure of starch, phenolic compounds, and the food processing conditions. In this review, the complexation between starch and phenolic compounds during (hydro)thermal and nonthermal processing is reviewed. A hypothesis on the complexation kinetics is developed to elucidate the mechanism of complexation between starch and phenolic compounds considering the reaction time and the processing conditions. The subsequent effects of complexation on the physicochemical properties of starch, including gelatinization, retrogradation, and digestion, are critically articulated. Further, the release of phenolic substances and the bioaccessibility of different types of starch–phenolics complexes are discussed. The review emphasizes that the processing-induced structural changes of starch are the major determinant modulating the extent and manner of complexation with phenolic compounds. The controlled release of complexes formed between phenolic compounds and starch in the digestive tracts can modify the functionality of starch-based foods and, thus, can be used for both the modulation of glycemic response and the targeted delivery of phenolic compounds.     

Composition and health effects of phenolic compounds in hawthorn (Crataegus spp.) of different origins

Epicatechin, aglycons and glycosides of B-type oligomeric procyanidins and flavonols, phenolic acids and C-glycosyl flavones are the major groups of phenolic compounds in hawthorn (Crataegus spp). The total content of phenolic compounds is higher in the leaves and flowers than in the fruits. Procyanidins dominate in the fruits, whereas flavonol glycosides and C-glycosyl flavones are most abundant in the leaves. Genotype and developmental/ripening stage have strong impacts. Procyanidin glycosides and C-glycosyl flavones may be chemotaxonomic markers differentiating species and varieties of hawthorn. Future research shall improve the separation, identification and quantification of procyanidins with degree of polymerisation (DP) ≥ 6, procyanidin glycosides, C-glycosyl flavones and some flavonol glycosides. In vitro and animal studies have shown cardioprotective, hypolipidaemic, hypotensive, antioxidant, radical-scavenging and anti-inflammatory potentials of hawthorn extracts, suggesting different phenolic compounds as the major bioactive components. However, the varying and insufficiently defined composition of the extracts investigated, as a result of different raw materials and extraction methods, makes comparison of the studies very difficult. Clinical evidence indicates that some hawthorn extracts may increase the exercise tolerance of patients with congestive heart failure. More clinical studies are needed to establish the effects of hawthorn, especially in healthy humans.     

Optimisation,characterisation and quantification of phenolic compounds in olive cake

The phenolic compounds in extracts from pressed olive cake were investigated. Free phenolic compounds were extracted from olive cake using methanol. To liberate bound phenolic compounds, the olive cake was subjected to basic and acidic hydrolysis followed by methanol extraction. The individual phenolic compounds and antioxidant activity of the extracts were determined. The highest total phenolic content and antioxidant activity were obtained using methanol extraction for 12 h at 70 °C. The RP-HPLC profiles for full-fat and defatted olive cake showed that protocatechuic acid, hydroxybenzoic acid, sinapic acid, p-coumaric acid, rutin and hesperidin were the predominant free phenolic compounds. Meanwhile, syringic acid, sinapic acid, caffeic acid and protocatechuic acid were the predominant bound phenolic acids. A positive correlation was observed between total phenolic content and antioxidant activity. The results indicated that most of the phenolic compounds in olive products were present in their free forms (75–90% of total phenolic content), while bound phenolic compounds were only a small proportion (10–25%) of total phenolic content.     

Valorisation of sweet corn (Zea mays) cob by extraction of valuable compounds

The main objective of this study was to investigate the proximate, mineral and phytochemical compositions of sweet corn cob (SCC), often neglected and regarded as agricultural waste. Compositional analysis showed that more than 60% of SCC was composed of insoluble dietary fibre, with cellulose being the major constituent. Results also showed that SCC can be a good source of non-essential protein and minerals (phosphorus, potassium and manganese). SCC had a total phenolic content of 6.74 g GAE kg⁻¹ dry weight (DW), of which bound phenolics were predominant. The bound phenolics fraction showed the highest antioxidant capacity in all three antioxidant capacity assays (TEAC, FRAP and DPPH) and contained the highest amount of ferulic and p-coumaric acid. The main carotenoids present in SCC were β-carotene, zeaxanthin and lutein. This investigation shows that SCC can be a potential source of natural colorant (carotenoids), antioxidants (phenolics) and nutritional supplements (proteins and phytochemicals).     

Husk Tomato (Physalis ixocarpa Brot.) Waste as a Promising Source of Pectin: Extraction and Physicochemical Characterization

Husk tomato (Physalis ixocarpa Brot. var. Rendidora) waste was evaluated as a source of specialized pectin, and pectin extracted from this waste was characterized physicochemically. Fruit was blanched for 10 or 15 min and extracted in 0.1 N HCl for 15 to 25 min. Extracted pectin was subjected to physicochemical analysis. For all extraction conditions, the percentage of anhydrogalacturonic acid exceeded 60%, indicating that husk tomato was a good source of pectin. The degree of esterification of pectin molecules was 63% to 91%. The amount of extracted pectin decreased with increasing extraction time. The apparent viscosity of husk tomato pectin showed the characteristic behavior of pseudoplastic fluids. Neutral sugars were identified, and the amounts of 6 sugars (fucose, rhamnose, arabinose, galactose, glucose, and xylose) were quantified. Sugars identified in husk tomato pectin and present in the Rhamnogalacturonan I region, arabinose, galactose, and rhamnose suggest a highly branched structure, which will influence its future applications. Molecular weight values were 542 to 699 kDa, exceeding molecular weight values reported for commercial citrus pectins from 134 to 480 kDa. The extraction process significantly (P < 0.05) influenced the physicochemical properties of pectin. Up to 19.8% from the total amount of pectin in the husk tomato was extracted by 10 min of blanching and 20 min of a more heat treatment. Our findings indicate that husk tomato can be a good alternative source of pectin having highly distinctive physicochemical characteristics.     

An overview of the perception and mitigation of astringency associated with phenolic compounds

Astringency, as a kind of puckering, drying, or rough sensation, is widely perceived from natural foods, especially plants rich in phenolic compounds. Although the interaction and precipitation of salivary proteins by phenolic compounds was often believed as the major mechanism of astringency, a definitive theory about astringency is still lacking due to the complex oral sensations. The interaction with oral epithelial cells and the activation of trigeminal chemoreceptors and mechanoreceptors also shed light on some of the phenolic astringency mechanisms, which complement the insufficient mechanism of interaction with salivary proteins. Since phenolic compounds with different types and structures show different astringency thresholds in a certain regularity, there might be some relationships between the phenolic structures and perceived astringency. On the other hand, novel approaches to reducing the unfavorable perception of phenolic astringency have been increasingly emerging; however, the according summary is still sparse. Therefore, this review aims to: (a) illustrate the possible mechanisms of astringency elicited by phenolic compounds, (b) reveal the possible relationships between phenolic structures and perception of astringency, and (c) summarize the emerging mitigation approaches to astringency triggered by phenolic compounds. This comprehensive review would be of great value to both the understanding of phenolic astringency and the finding of appropriate mitigation approaches to phenolic astringency in future research.