用于调理鸡肉的大气等离子体冷杀菌工艺优化

本文采用大气等离子体放电技术处理调理鸡肉表面,在不损伤风味的情况下对其杀菌工艺进行研究。本研究以调理鸡肉的杀菌率和感官评价为指标,通过放电功率、处理时间、气体流量单因素实验探究冷杀菌工艺条件,并采用响应面法对其进行优化。结果表明,大气等离子体放电处理调理鸡肉的优化参数为气体流量为40 L/min,放电时间52 s,放电功率450 W,杀菌率达到96.34%±0.32%,与理论杀菌率相差3.04%。这些数据表明,大气等离子体技术可对食品表面进行非热处理,具有明显的杀菌效果。     

Antioxidant, antihypertensive and antimicrobial properties of ovine milk caseinate hydrolyzed with a microbial protease

BACKGROUND: Bioactive peptides might be released from precursor proteins through enzymatic hydrolysis. These molecules could be potentially employed in health and food products. In this investigation, ovine milk caseinate hydrolysates obtained with a novel microbial protease derived from Bacillus sp. P7 were evaluated for antioxidant, antimicrobial, and angiotensin I‐converting enzyme (ACE)‐inhibitory activities. RESULTS: Antioxidant activity measured by the 2,2′‐azino‐bis‐(3‐ethylbenzothiazoline)‐6‐sulfonic acid method increased with hydrolysis time up to 2 h, remaining stable for up to 4 h. Hydrolysates showed low 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging abilities, with higher activity (31%) reached after 1 h of hydrolysis. Fe²⁺‐chelating ability was maximum for 0.5 h hydrolysates (83.3%), decreasing thereafter; and the higher reducing power was observed after 1 h of hydrolysis. ACE‐inhibitory activity was observed to increase up to 2 h of hydrolysis (94% of inhibition), declining afterwards. 3 h hydrolysates were shown to inhibit the growth of Bacillus cereus, Corynebacterium fimi, Aspergillus fumigatus, and Penicillium expansum. CONCLUSION: Ovine caseinate hydrolyzed with Bacillus sp. P7 protease presented antioxidant, antihypertensive, and antimicrobial activities. Hydrolysis time was observed to affect the evaluated bioactivities. Such hydrolysates might have potential applications in the food industry. Copyright © 2011 Society of Chemical Industry     

狗肝菜功能性成分的抗氧化活性

以狗肝菜为原料,对其中的黄酮、多糖、多酚等功能性成分进行提取,并对其抗氧化活性进行研究。结果表明:狗肝菜中含有丰富的黄酮、多糖和多酚类物质,其含量分别为2.4、180.5mg/g和61.2mg/g(以干基计)。抗氧化实验表明:狗肝菜黄酮、多糖和多酚具有较强的清除DPPH自由基和.OH的能力,对DPPH自由基的清除率分别为76.7%、88.2%和35.8%,对.OH的清除率分别为90.8%、95.7%和80.9%。     

Molecular Characterization and Identification of Bioactive Peptides Producing Lactobacillus sps. Based on 16S rRNA Gene Sequencing

In the present study, 3 bacterial cultures were isolated from faecal samples of human infant. The biochemical traits showed similarity with Lactobacillus sps and 16S rRNA sequence analyses, confirmed as Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus rhamnosus. The cultures were screened for their proteolytic activity and good ability to release peptides from milk proteins was found. Hence, these bacteria were used as a proteolytic starter culture for the fermentation of skim milk and whey for the liberation of small peptides. Bioactive nature of the peptides released from whey and skim milk was tested, and results demonstrated that peptides obtained after fermentation of whey and skim milk by Lactobacillus strains showed antimicrobial activity against all the pathogens causing food borne infections in humans. These peptides also indicated antioxidant as well as ACE (angiotensin-converting enzymes) inhibitory activity.     

Effect of drying conditions on bioactive compounds and antioxidant activity of broccoli (Brassica oleracea L.)

The effect of air‐drying parameters on antioxidant activity and changes in antioxidant compounds of broccoli (Brassica oleracea L.) were studied. Broccoli samples were dried to 70 g kg^?1 moisture content using temperatures ranging from 50 to 100 °C and air flow‐rates from 1.20 to 2.25 m s^?1, resulting in drying times from 25 to 90 min. Temperature, owing to its positive effect on the oxidation kinetics, was negatively correlated with ascorbic acid and free and total polyphenol contents but not with kaempferol, even though the sample dried at the highest temperature showed the lowest kaempferol content. The air flow‐rate was positively correlated with the total (TPP) and free (FPP) polyphenol contents because it led to a reduction in the drying time. No correlation was found between air flow‐rate and kaempferol content. Air flow‐rate and temperature positively affected the antioxidant activity by reducing the drying time. High‐temperature, short‐time processes maximised the antioxidant activity of broccoli owing to the negative effect of drying time on antioxidant activity. The antioxidant activity of broccoli was positively and significantly correlated with the FPP content but not with TPP and kaempferol. The evaluation of hydroxymethylfurfural content as an indicator of the occurrence of a Maillard reaction in dried broccoli did not support the hypothesis of a contribution of MRPs to the antioxidant activity of dried broccoli. Copyright © 2006 Society of Chemical Industry     

Chemical composition, antioxidant and antimicrobial properties of Rapa Catozza Napoletana (Brassica rapa L. var. rapa DC.) seed meal, a promising protein source of Campania region (southern Italy) horticultural germplasm

BACKGROUND: The present study is the first effort in a comprehensive evaluation of the nutritive and biological properties of the meal from Rapa Catozza Napoletana (RCN) (Brassica rapa L. var. rapa) cultivar seeds as a new and alternative source of proteins. RESULTS: RCN seed meal revealed a good protein content (382.0 g kg^?1) compared with conventional Brassica defatted meals. Total glucosinolates (6.0 g kg^?1) were comparable to or even lower than those reported for other yellow‐ and brown‐seeded cultivars. Low levels of both sinapine and phytic acid (10.0 and 10.0 g kg^?1 respectively) suggest a minor influence of these compounds on meal mineral availability. The meal revealed quite a high polyphenolic content (13.0 g kg^?1) composed of flavonol and hydroxycinnamic derivatives. With regard to meal biological properties, a higher radical‐scavenging potential than reducing capacity and a broad antimicrobial spectrum, mainly against food‐borne pathogens, were detected. CONCLUSION: RCN seed meal could be highly regarded as a component of human nutrition and animal feed for its good protein content, desirable amino acid profile and low antinutrient concentration. Results for the sample indicated appreciable antiradical activity and good properties for meal stability. Copyright © 2011 Society of Chemical Industry     

菱茎多酚的提取工艺及其抗氧化、抑菌活性研究

目的:研究菱茎多酚的超声波辅助提取工艺及其体外抗氧化、抑菌活性。方法:以菱茎为材料,采用正交实验对菱茎多酚的提取工艺进行优化;通过测定菱茎多酚的DPPH、ABTS自由基清除力及还原力来评价其体外抗氧化活性;采用滤纸片扩散法测定菱茎多酚对6种腐败微生物的抑菌活性。结果:菱茎多酚的最佳提取工艺条件为乙醇浓度60%、pH1、提取温度70 ℃、提取时间35 min、料液比1：35 (g/mL),此工艺条件下多酚的提取得率为67.31 mg GAE/g DW;菱茎多酚对DPPH、ABTS自由基清除力和对Fe³⁺还原力(FRAP)的IC₅₀值分别为228.34、220.57、152.00 μg/mL;对金黄色葡萄球菌、蜡样芽孢杆菌、大肠杆菌、腐败希瓦氏菌、青霉和酿酒酵母的最小抑菌浓度(MIC)分别为6.25、3.13、0.20、0.39、1.56、0.78 mg/mL。结论:菱茎多酚具有良好的抗氧化和抑菌活性,可作为潜在抗氧化剂和抑菌剂的来源进一步开发利用。     

Influence of the interactions between tea (Camellia sinensis) extracts and ascorbic acid on their antioxidant activity: analysis with interaction indexes and isobolograms

Products containing natural additives, including antioxidants, are usually perceived by consumers as safer than those with synthetic ones. Natural antioxidants, besides having a preservative activity, may exert beneficial health effects. Interactions between antioxidants may significantly change their antioxidant activity, thus in designing functional foods or food/cosmetic ingredients knowledge about the type of interactions could be useful. In the present study, the interactions between ascorbic acid (AA; vitamin C) and different black and green tea extracts and the influence on their antioxidant activities were investigated. The antioxidant activities of tea extracts and their mixtures with AA prepared in several different weight ratios were measured using the trolox equivalent antioxidant capacity (TEAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric-reducing antioxidant power (FRAP) methods. The type of interaction was determined by interaction indexes and isobolograms. It was found that the weight ratio of extracts to AA significantly influenced the antioxidant activity of a mixture and the type of interaction between these components. The weight ratio of tea extract to AA can cause the change of interaction, e.g. from antagonism to additivism or from additivism to synergism. The observed differences in the type of interactions were probably also a result of different extracts’ polyphenol composition and content. The type of interaction may also be affected by the medium in which extracts and AA interact, especially its pH and the solvent used. To obtain the best antioxidant effect, all these factors should be taken into account during the design of a tea extract–AA mixture.     

Effects of Ascorbic Acid Applied by Two Hydrocooling Methods on Physical and Chemical Properties of Green Leaf Lettuce Stored at 5°C

ABSTRACT: The effect of ascorbic acid applied by 2 hydrocooling methods on chemical and physical properties of'Waldmann's'dark green leaf lettuce ( Lactuca sativa L.) during cold storage was evaluated. Lettuce was immersed (in 1% ascorbic acid or tap water) or sprayed (with 1% ascorbic acid or tap water) or left untreated (control). Treatment solutions for immersion or spraying were applied at 5°C for 2 min. Afterward, lettuce was packaged in moisture impermeable plastic bags and stored at 5°C for up to 21 d. Analytical assays included total ascorbate content, 2,2'-azinobis (3-ethylbenz-thiazoline-6-sulphonic acid) (ABTS^˙+) Trolox equivalent antioxidant capacity, total phenolic content, relative water content and instrumental color. Lettuce was analyzed at 5 time intervals: before treatment application and at days 1, 7, 14, and 21 of storage time. Hydrocooling of leaf lettuce by immersion or spraying using 1% ascorbic acid solution increased total ascorbate content for up to 7 d, with an increase of more than 300% in total ascorbate content on day 1 compared with its initial value before treatments. However, the ABTS antioxidant capacity of leaf lettuce did not increase in ascorbic acid treated lettuce even though total ascorbate content increased. Ascorbic acid immersion was the only treatment that maintained the relative water content of leaf lettuce for 21 d. Further experimentation with the application of ascorbic acid during hydrocooling is needed to assess its usefulness as a processing treatment.     

Evaluation of hot and cold extraction of bioactive compounds in teas

This study evaluated the bioactive compounds of different types of tea by comparing hot and cold infusions. A multivariate data analysis was carried out, where the principal components analysis (PCA) and hierarchical cluster analysis (HCA) were used. Phenolic compounds varied between 267.27–2896.00 mg GAE L^?1 and 215.10–7351.33 mg GAE L^?1 for hot (80 °C) and cold extraction (20–25 °C), respectively. In the case of their antioxidant activity, results with DPPH were 43.10‐73.67% for hot extraction and 46.80‐77.13% for cold extraction. The average values for the ABTS˙⁺ method ranged between 2535.43 and 33 300.17 μmol TE L^?1 and between 1110.34 and 38 300.67 μmol TE L^?1, respectively, for hot and cold extraction. Different compounds were identified by liquid chromatography in the samples evaluated, where caffeine presented the higher concentrations in the teas. Samples of green and black tea (hot extraction) and white tea (cold extraction) showed bacteriostatic activity for S. aureus and E. coli. No extract had any bactericide activity. The current study revealed that cold infusion was more efficient in the extraction of bioactive compounds.     

海蜇胶原蛋白肽的生物活性研究

以海蜇加工下脚料为原料提取胶原蛋白,酶解制备胶原蛋白肽并对酶解液进行抽滤分离,并对所得不同分子量的胶原蛋白肽进行生物活性研究。结果表明:抽滤分离到四种不同分子量的胶原蛋白肽:分子量>10 kDa(JCP1)、分子量3~10 kDa(JCP2)、分子量1~3 kDa(JCP3)和<1 kDa(JCP4)。生物活性研究表明,JCP1具有最强的超氧阴离子自由基清除能力和酪氨酸酶双酚酶抑制效果,其IC₅₀值分别为22.6和11.96 mg/mL,JCP1对酪氨酸酶的抑制类型为可逆混合竞争型抑制;JCP3具有最强的还原力、羟自由基、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)自由基清除能力和血管紧张素转换酶(ACE)抑制活性,其IC₅₀值分别为14.9、2.21、0.61和15.8 mg/mL;JCP4具有最强的1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力,其IC₅₀值为28.3 mg/mL。     

生物活性肽在营养保健中的应用

生物活性肽是一种保健食品功能因子,本文综述了生物活性肽的种类、生理功能,吸收机制、特点,生物活性作用。     

不同干燥方法对生姜叶活性成分和抗氧化活性的影响

为研究不同干燥方法对生姜叶活性成分和抗氧化能力的影响,以黄酮、多酚、精油含量及精油组分为活性成分指标,以DPPH·、ABTS⁺·及·OH清除率为抗氧化能力指标,对比阴干、晒干、烘干、冷冻干燥及真空干燥5种干燥方法对生姜叶的影响。结果表明,与新鲜生姜叶相比,经过不同干燥处理后生姜叶的活性成分含量及抗氧化能力均有所下降。其中,冷冻干燥处理后的生姜叶黄酮、多酚及精油含量均是最高,分别为21.62 mg/g、1.56 mg/g和1.91%;对DPPH·、ABTS⁺·和·OH的清除化能力最高,分别为70.42%、79.65%和63.41%。其次分别为烘干、真空干燥、阴干及晒干。通过GC-MS分析,新鲜及5种干燥方法得到的生姜叶精油共鉴定出33种组分,其主要组分为α-柏木烯、乙酸异龙脑酯、(Z)-3,7-二甲基-2,6-辛二烯醛及甲基庚烯酮,主要分为7大类,分别为萜烯类、醇类、醛类、酚类、酸类、酮类及酯类。综合比较,冷冻干燥对生姜叶中的活性成分及抗氧化能力保留效果最好。     

瘤背石磺活性多肽制备工艺优化及其抗氧化性探究

以瘤背石磺为原料,采用响应面法优化瘤背石磺活性多肽的制备工艺,考察Na Cl浓度、液固比、温度和提取时间对羟基自由基清除率的影响。结果表明:最优提取条件为Na Cl浓度0.09%,液固比57 m L/g,提取时间2.5 h,在此条件下羟基自由基清除率最大,预测值为33.09%,实测值为33.34%,实测值与预测值相接近,且相对误差只有0.76%,表明响应面法得到的最佳提取条件合理可行。天然活性多肽体外抗氧化活性实验结果表明:其对羟基自由基、DPPH自由基、H2O2有较好清除能力,还具有一定还原能力以及亚铁离子螯合能力。总体而言,瘤背石磺天然活性多肽表现出一定的体外抗氧化活性,具有良好的开发前景。      

干腌火腿中生物活性肽功能特性研究进展

干腌火腿在加工过程中由于内源酶和微生物作用,蛋白质被分解产生许多具有生物活性的肽,这些肽的功能特性主要包括抗氧化、降血压和抗菌,具有很高的研究价值和广阔的应用前景.本文对干腌火腿中生物活性肽的形成机理以及其发挥各种功能特性的机理进行综述.     

Polyphenols, Anthocyanins, Ascorbic Acid, and Radical Scavenging Activity of Rubus, Ribes, and Aronia

ABSTRACT: Total polyphenols, total anthocyanins, and reduced ascorbic acid were evaluated in berries belonging to the genera Rubus, Ribes, and Aronia by means of spectrophotometric and high-performance liquid chromatography (HPLC) techniques. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the fruit extracts was tested. Total polyphenols ranged from 140.6 to 888.5 mg/100 g fresh weight (FW), total anthocyanins ranged from 22.0 to 460.5 mg/100 g FW, and reduced ascorbic acid ranged from 12.4 to 153.8 mg/ 100 g FW. The average EC50 values for Aronia melanocarpa, Ribes nigrum, Ribes rubrum, Rubus fruticosus, and Rubus idaeus were 1.8, 2.8, 5.3, 6.4, and 8.2 mg FW, respectively. The results indicate that the fruits tested are good sources of natural antioxidants.