预处理工艺对黑蒜功能性成分、抗氧化活性影响及相关性研究

分别利用微生物、冷冻和高温高压3种工艺对白蒜进行预处理,发酵制备黑蒜,对黑蒜发酵过程中的色差、褐变程度、总酚、蛋白质、总酸、pH、S-烯丙基-L-半胱氨酸(S-allyl-L-cysteine,SAC)、5-羟甲基糠醛(5-hydroxymethylfurfural,5-HMF)等理化指标进行监测,并对羟自由基清除能力、ABTS自由基清除能力、还原力等抗氧化能力及相关性进行解析。结果表明,不同预处理工艺制备的黑蒜,在其发酵过程中,色差、褐变程度均呈现出先上升后趋于稳定的趋势;总酚、可滴定酸、可溶性蛋白质含量等均呈现增加的趋势,与羟自由基清除能力、ABTS自由基清除能力、还原力呈现出正相关的趋势;发酵制备的黑蒜中SAC含量均高于鲜蒜,不同预处理工艺显著降低了黑蒜中的5-HMF含量。该研究为高品质、高营养黑蒜的发酵和可能关键危害因子5-HMF含量的调控提供了基础数据,为降低食品中5-HMF含量做出可行性研究。     

黑蒜加工过程中主要营养物质及抗氧化活性变化的研究

目的探究大蒜在发酵成为黑蒜过程中主要营养物质及抗氧化活性的变化。方法将新鲜大蒜置于高温密闭环境中发酵,定期测定蒜样的水分、还原糖、总酸、蛋白质及总酚的含量和抗氧化活性。结果在高温高湿条件下,随着发酵时间的延长,蒜瓣水分逐渐丧失,还原糖、总酸、蛋白质、总酚含量相对提高, 25 d时黑蒜的还原糖含量较鲜蒜增加12.19%,总酚含量提高6.7倍,蛋白质含量增加3.14 mg/g DW;抗氧化性能总体增加, DPPH清除能力提升了2.6倍。结论适宜的条件下发酵形成的黑蒜具有更高的营养价值和抗氧化活性。     

花蟹肉酶解物美拉德反应产物的抗氧化性

为研究花蟹肉酶解物美拉德反应产物(MRPs)的理化性质和功能属性,用花蟹肉酶解物(P)分别与木糖(X)、葡萄糖(G)、乳糖(L)和果糖(F)进行模式美拉德反应,并测定MRPs的褐变程度和pH值变化,同时通过对MRPs进行DPPH自由基清除能力、还原能力、OH自由基清除能力和Fe2+螯合能力的测定,评价其抗氧化能力。结果表明,随着加热时间的延长,各MRPs的褐变程度增加,pH值下降,DPPH自由基清除能力、还原能力和OH自由基清除能力逐渐增加,但各MRPs的Fe2+螯合能力下降。还原糖种类不同,MRPs的抗氧化性不同,各MRPs的DPPH自由基清除能力、还原能力和OH自由基清除能力由强到弱依次为:木糖-花蟹肉酶解物(X-P)、果糖-花蟹肉酶解物(F-P)、葡萄糖-花蟹肉酶解物(G-P)、乳糖-花蟹肉酶解物(L-P)。     

不同加工工艺对黑蒜产品品质的影响

黑蒜是一种新型大蒜加工制品,通过不同加工工艺得到两种不同的产品黑蒜1号和黑蒜2号,其中黑蒜1号的生产周期为黑蒜2号的3倍。本研究比较了两种加工工艺对黑蒜基本营养成分、蒜氨酸含量以及自由基清除能力的影响。研究表明:与新鲜大蒜相比,黑蒜的水分含量较少约为40%,湿基中的可溶糖、蛋白质和多酚显著增多(P0.01),蒜氨酸含量减少。而干基中的营养物质除多酚外,其余成分都减少,脯氨酸和精氨酸急剧降低,变异系数分别为1.03和1.12。湿基对OH·的清除能力基本一致,对DPPH·的清除力为新鲜蒜的2倍。黑蒜1号的粗蛋白含量低于黑蒜2号,可溶糖、多酚、蒜氨酸皆高于黑蒜2号,粗蛋白和多酚变异系数达到0.20左右,各组分间存在显著差异(P0.05)。在不同浓度下对自由基清除能力相同,当浓度为0.05 g/m L时,对OH·和DPPH·的清除率达到了90%以上。电子舌可以有效的区别两种产品。     

保压时间对黑蒜部分营养成分和抗氧化作用的影响

本文采用超高压预处理与发酵联用的方法制备了黑蒜,同时研究了保压时间对黑蒜的抗氧化作用的影响,并初步探讨了黑蒜的营养成分与抗氧化作用之间的关系。结果表明,超高压预处理的时间对白蒜和发酵黑蒜的营养成分含量有显著的影响。不同保压时间预处理后,白蒜和黑蒜的总糖含量有所下降,并且白蒜发酵成黑蒜后总糖含量也有所下降。而黑蒜中的总酚和黄酮含量明显高于白蒜。保压时间为15 min时,黑蒜总酚含量达到最高,为13.20 mg/g,未经超高压预处理黑蒜的黄酮含量最高,达到5.23 mg/g。超高压预处理并发酵后,黑蒜的抗氧化能力明显高于白蒜。黑蒜的还原能力、对羟基自由基的清除能力分别在保压时间5和20 min时最高,未经超高压预处理的黑蒜对1,1-二苯基-2-三硝基苯肼(DPPH)的清除作用最大。     

油茶籽美拉德反应及其产物抗氧化性

为了研究油茶籽美拉德反应发生规律,采用不同加热时间与温度处理油茶籽,并测定反应前后油茶籽中还原糖含量、游离氨基酸含量、水分含量、pH值、褐变程度、色值以及美拉德反应产物及其抗氧化性等指标。结果表明:油茶籽在120℃和150℃的温度下随着加热时间延长还原糖含量、游离氨基酸含量、pH值和水分降低最多。油茶籽在120℃和150℃的温度下加热60 min时产生美拉德产物最多且具有明显抗氧化能力,清除DPPH·自由基率分别是43. 06%和48. 87%;清除ABTS~+·自由基率分别是81. 43%和89. 81%。本研究对深入了解油茶籽在加工过程中内部化学物性变化规律及其氧化稳定性特性具有重要意义。     

乳清蛋白菊粉糖基化复合物的褐变特性与抗氧化活性

以褐变程度及抗氧化活性为检测指标,研究湿热反应条件对乳清蛋白菊粉糖基化复合物的褐变特性与抗氧化活性的影响。研究结果表明:反应物浓度越大,反应温度越高,乳清蛋白菊粉糖基化产物的褐变强度越大,抗氧化活性越强;起始反应pH值越大,乳清蛋白菊粉糖基化产物的褐变强度及还原能力越强,而其DPPH.清除能力呈现先升高后降低的趋势。当反应物浓度为6%,温度为100℃,起始反应pH值为9时,所获得的乳清蛋白糖基化产物抗氧化活性较强。     

酪蛋白-木糖体系美拉德反应产物的抗氧化活性

研究评价了由酪蛋白-木糖模拟体系产生的美拉德反应产物的抗氧化活性,考察了反应过程中体系的pH、褐变和中间产物的变化,并测定了美拉德反应产物对金属离子(Cu2+和Fe2+)的螯合能力、自由基清除能力(.OH、DPPH.和ABTS.)以及其还原能力。结果表明,模拟体系的酸度和褐变均随反映的进行而逐渐增加,中间产物在反应初期大量形成;美拉德反应产物对Fe2+的螯合能力要明显强于对Cu2+的螯合能力;美拉德反应产物对DPPH.和ABTS.具有较强的清除作用,而对.OH的清除作用较弱;美拉德反应产物的还原能力随反应时间的延长而逐渐增大。     

Antioxidative activity and scavenging effects on active oxygen of xylose-lysine maillard reaction products

The antioxidative activity and scavenging effects on active oxygen of Maillard reaction products (MRP) prepared by heating xylose and lysine (XL) at a molar ratio 1:2 and pH 9.0 for 1.5 h (XL-1 to XL-5) were investigated. The antioxidative activity and browning intensity of XL MRP increased with increasing duration of reaction, but XL-1 and XL-2 MRP showed greater reducing power than other samples (P < 0.05). All XL MRP showed scavenging activity on 1,1-diphenyl–2-picrylhydrazyl (DPPH) radical. XL-1, XL-2 and XL-3 MRP exhibited about 50% reduction in absorbance of superoxide. Scavenging effects of XL MRP on DPPH radical and superoxide were markedly decreased after decolorization with Sep-Pak Cartridge C18, indicating that the browning pigment might contain components that can scavenge superoxide or donate hydrogen atoms. The electron paramagnetic resonance spectra indicated that XL MRP had scavenging activity on the hydroxyl radical; this scavenging effect depended on dose (r = 0.99) and increased with increasing duration of reaction. Based on these data, the antioxidative activity of XL MRP may be attributed to the combined effects of reducing power, donation of hydrogen atoms and scavenging of active oxygen.     

美拉德反应修饰的鲢鱼肽抗氧化活性初探

美拉德反应修饰是改善肽抗氧化活性的新途径。本实验采用鲢鱼肽与葡萄糖作为反应原料,以不同的浓度反应0,2,4,6,8,10h,并分别对棕色变化、还原糖、游离氨基、还原力和DPPH自由基清除活性进行了测定,结果表明美拉德反应产物均表现出很好的抗氧化活性,还原力在一定的范围内随时间的增加而增强,E组(10g鲢鱼肽和5g葡萄糖)最大,在10h时为A组的6.09倍。清除DPPH自由基的活性则在2h时达到较高的值,E组具有最高的的自由基清除率为64.45%。美拉德反应产物的还原力与DPPH自由基清除活性不一致,而且其抗氧化能力不完全依赖于产物的褐变程度。     

不同品种和加工工艺制得黑蒜的成分分析

目的比较不同品种和加工工艺制得黑蒜的成分。方法以独头蒜和多瓣蒜为试验材料,采用湿热加工法制备黑蒜,与相应鲜蒜和干热加工法生产的黑蒜(市售)比较,分析其主要成分的变化。采用苯酚硫酸法测定总糖含量,福林酚法测定多酚样物质含量,DPPH、ABTS、超氧阴离子自由基清除率以及FRAP法测定抗氧化性,硫酸钡吸光比浊法测定总硫含量,高效液相法测定含硫化合物含量。结果独头蒜与多瓣蒜相比,其总糖含量较高,但多酚样物质含量无明显差异;其DPPH自由基清除率较低,但ABTS和超氧阴离子自由基清除率以及总抗氧化能力无明显差异;除蒜氨酸含量稍高外,总硫、二烯丙基二硫(diallyl disulfide,DADS)和二烯丙基三硫(diallyltrisulfide,DATS)含量均无明显差异。无论独头蒜还是多瓣蒜,湿热加工成黑蒜后,总糖含量和多酚样物质均含量增高;ABTS、DPPH、超氧阴离子自由基清除率和总抗氧化能力均显著增高;蒜氨酸、DADS和DATS含量均降低,但S-烯丙基半胱氨酸(S-allyl cysteine,S-AC)含量增高,总硫含量无明显变化。湿热加工法制备的黑蒜与市售黑蒜相比,湿法加工黑蒜其多酚样物质含量较高,而市售黑蒜总糖含量较高;其ABTS、DPPH、超氧阴离子自由基清除率和总抗氧化能力均较高;蒜氨酸、DADS和DATS含量均较高,而S-AC含量较低。结论独头蒜与多瓣蒜制备而得的黑蒜的主要成分无明显差异。湿热加工法制备的黑蒜与市售黑蒜相比,抗氧化性较强,但S-AC含量较低。不同大蒜品种和加工工艺制备黑蒜可以为黑蒜生产和功能特性探究提供依据。     

大蒜、生姜、洋葱醇提物抗氧化活性的比较

通过测定大蒜、生姜、洋葱醇提物的还原力、螯合能力及其对DPPH自由基、超氧阴离子自由基、羟基自由基的清除能力研究了它们的抗氧化活性。实验结果表明,大蒜、生姜、洋葱醇提物均具有较强的还原力和螯合能力,对超氧阴离子自由基、羟基自由基和DPPH自由基具有不同效果的清除作用,即大蒜、生姜、洋葱醇提物均具有显著的体外抗氧化活性,值得进一步研究开发。     

Antiyeast Potency of Heated Garlic in Relation to the Content of Allyl Alcohol Thermally Generated from Alliin

ABSTRACT:  The appearance of antiyeast activity in heated garlic extract was influenced by the temperature, heating time, and pH. The maximum antiyeast activity was attained at the temperature range between 110 and 130 °C for the heating time range of 90 and 30 min, respectively. Reduced antiyeast activity occurred above 130 °C. More potent antiyeast activity was generated when the pH of the garlic extract was adjusted to and below 4.0. The sensitivity to the antiyeast activity of heated garlic or heated alliin was quite different depending on the yeast strain. Species belonging to Zygosaccharomyces were the least sensitive, while Candida utilis and Pichia membranaefaciens were among the most sensitive. The alliin content of the garlic was in the range of 0.5% to 1.32%. When garlic extracts were heated at 121 °C for 120 min, the content of allyl alcohol generated from alliin through thermal degradation was in the range of 0.08% to 0.16%. The allyl alcohol produced upon heating was positively proportional to the content of alliin in garlic. The antiyeast potency expressed as the minimum inhibitory concentration (MIC) was negatively proportional to the content of allyl alcohol and thus to the content of alliin.     

Antioxidant capacity of Maillard reaction products’ fractions with different molecular weight distribution from chicken bone hydrolysate – galactose system

Maillard reaction products (MRP) were prepared from an aqueous chicken bone hydrolysate (CBPH) – galactose systems by heating at 100 °C for up to 7.5 h without pH control, and then separated into the <3‐, 3‐ to 10‐ and >10‐kDa fractions using ultrafiltration. Antioxidant capacity and spectral properties of these MRP fractions were studied. The scavenging activity towards DPPH and hydroxyl radicals as well as reducing power of each MRP fraction increased with the heating time, in accordance with the increase in UV absorbance, browning and fluorescence intensity. For the same MRP, the fraction with high molecular weight (MW) demonstrated the stronger radical scavenging activity and reducing power than that with low MW. Radical scavenging activities of MRP fractions largely depended on their MW, while their reducing powers were more related to the reaction progress. These results suggested that antioxidant capacity of MRP fractions should be positively related to its molecular size.     

不同豇豆中酚类含量与抗氧化活性

为深入了解豇豆的营养价值,以11个不同品种的豇豆样品为原料,对其总酚含量、总黄酮含量及抗氧化活性(总还原能力、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力、·OH清除能力)进行分析,并讨论酚类物质含量及抗氧化活性的相关性。结果表明,不同品种的豇豆酚类物质含量和抗氧化活性差异显著。在测定的样品中,新杂1号表现出最高的总酚含量(5.59 mg GAE/g)、总黄酮含量(4.12 mg CAE/g)及抗氧化活性(总还原能力和DPPH自由基清除能力);豇豆中总酚含量、总黄酮含量与总还原能力、DPPH自由基清除能力之间有极显著相关性(P0.01),与·OH清除能力之间没有显著相关性。     

INHIBITORY EFFECT OF ANTHOCYANIN EXTRACT FROM SEED COAT OF BLACK BEAN ON PERICARP BROWNING AND LIPID PEROXIDATION OF LITCHI FRUIT DURING STORAGE

ABSTRACT

Anthocyanins were extracted from seed coats of black beans (Glycine max[L.]) and the inhibitory effects of anthocyanin extract on pericarp browning and lipid peroxidation of litchi fruit were investigated. Litchi fruit were infiltrated for 3 min with 0 (control) or 50 mg/L of anthocyanin extract at a reduced pressure of 53 kPa, then packed in 0.03 mm thick polyethylene bags, and finally stored at 28C for 6 days. Changes in browning index, contents of anthocyanins and total phenol, peroxidase (POD) activity, levels of relative leakage rate and lipid peroxidation, α,α‐diphenyl‐β‐picrylhydrazy (DPPH) radical scavenging activity and reducing power were evaluated. Application of anthocyanin extract from black bean delayed pericarp browning of litchi fruit during storage, which was associated with reduced POD activity and higher contents of anthocyanins and total phenol. Moreover, the anthocyanin extract was found to have a direct inhibition on the POD activity in vitro. Furthermore, application of the anthocyanin extract apparently reduced lipid peroxidation and relatively maintained membrane integrity, which may account for browning inhibition to an extent. Finally, higher DPPH radical scavenging activity and reducing power of the fruits treated with the anthocyanin extract than control fruits possibly benefited in scavenging free radicals and reducing lipid peroxidation. It is, therefore, suggested that inhibited POD activity and reduced lipid peroxidation by the anthocyanin extract from seed coats of black beans were responsible for the inhibition of pericarp browning of litchi fruits.

PRACTICAL APPLICATIONS

Lipid peroxidation is a major cause of quality deterioration of postharvest fruits and vegetables. Some synthetic antioxidants are beneficial in inhibiting lipid peroxidation. However, considering that synthetic antioxidants, such as butylhydroxyanisole and butylated hydroxytoluene (BHT), have potential toxicity, the use of natural extracts to extend the shelf life of postharvest fruits and vegetables is a tendency. In our previous study, it has been found that anthocyanin extract from litchi pericarp has stronger antioxidant activities or free radical scavenging activities than BHT and ascorbic acid ( Duan et al. 2007 ). In this study, the application of anthocyanin extract from seed coat of black soybean showed reduced lipid peroxidation and pericarp browning. It could be used potentially as a postharvest technology for reducing or replacing the use of other chemicals, but it requires further investigation.     

Evaluation of pre‐heating and extraction solvents in antioxidant and antimicrobial activities of garlic,and their application in fresh pork patties

The objectives of this study were to screen the optimum conditions for antioxidant and antimicrobial activities of garlic as affected by pre‐heating and different extraction solvents, and to evaluate the antioxidant and antimicrobial effects of these extracts in ground meat during refrigerated storage. Methanol extracted garlic had a greater total phenolic content, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH)‐radical scavenging activity and reducing power than water extracted one (P < 0.05), whereas the latter had a greater yield and iron chelating ability than the former (P < 0.05). Moreover, water extract from fresh garlic (WEFG) and methanol extract from heated garlic (MEHG) produced an inhibition zone against Escherichia coli O157:H7 and Listeria monocytogenes. The addition of garlic extracts (WEFG, MEHG and their combinations WEFMEHG)) to pork patties decreased the pH, hunter a values (redness), thiobarbituric acid substances values and the number of total plate count and Enterobacteriaceae (P < 0.05), while the hunter b values (yellowness) increased (P < 0.05). Results of this study indicated that the use of the garlic extracts was able to control lipid oxidation and microbial growth in pork patties.     

Antioxidative activity of Mungoong,an extract paste,from the cephalothorax of white shrimp (Litopenaeus vannamei)

The antioxidative activity of Mungoong, an extract paste, from the cephalothorax of white shrimp (Litopenaeus vannamei) was studied. Extraction media were shown to affect the antioxidative activity and properties of resulting extracts from Mungoong. Distilled water exhibited the highest efficacy in extracting the antioxidants from Mungoong, as evidenced by the highest ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and DPPH (2,2-diphenyl-1-picryl hydrazyl) radical scavenging activity as well as ferric reducing activity power (FRAP), compared with distilled water/ethanol mixture (1:1, 1:2 and 2:1) and ethanol. UV-absorbances at both 280 and 295 nm (A₂₈₀, A₂₉₅), browning intensity (A₄₂₀) and fluorescence intensity were also highest in the extract using distilled water. ABTS and DPPH radical scavenging activity and FRAP of water extract, increased linearly with increasing concentration. Good correlation between ABTS and DPPH radical scavenging activity; DPPH radical scavenging activity and FRAP; ABTS radical scavenging activity and FRAP were observed, suggesting that antioxidants in the extract, possessed the capability of scavenging the radicals together with reducing power. Antioxidants in the water extract from Mungoong showed high stability over the wide pH ranges (2–11) and temperature up to 100 °C, in which the activity of more than 80% remained. MALDI-TOF analysis revealed that water extract contained the peptides having the mass ranges of m/z 400–1000 and 4000–7000.     

Influence of heating on the polyphenolic content and antioxidant activity of grape seed flour

Abstract: The production of grape seed flour (GSF) from a waste product generated during winemaking, is of interest in product development applications due to its potential health benefits. However, before GSF can used in baking as a source of additional antioxidants, research on its heat stability is required. The overall objective of this study was to assess changes in phenolic content and antioxidant activity of GSF during heating. Merlot GSF was heated at 5 temperatures (120 to 240 °C) for 0 to 90 min. At each time/temperature combination, total phenolic content (TPC), total flavanoid content (TFC), Trolox equivalent antioxidant capacity (TEAC), 2,2 diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging, and ferric ion reducing antioxidant power (FRAP) of the extracts were determined. Specific polyphenolic compounds, including catechin, gallocatechin, epicatechin, and gallic acid were also measured. Results showed that when Merlot GSF was heated to ≥180 °C, significant decreases in the TPC and antioxidant activity, measured using FRAP, DPPH, and TEAC, were observed. Longer heating times also caused a reduction in antioxidant capability. Catechin and epicatechin content decreased with increasing heating temperature while gallocatechin and gallic acid content increased. Both catechin and epicatechin content had strong positive correlations (r > 0.91) with TPC and TFC, as well with FRAP and TEAC, suggesting that the GSF antioxidant activity is related to the presence of these particular compounds. Overall, while a decrease in antioxidant content was observed during heating, this occurred at higher baking temperatures. Thus GSF may be suitable for use as an ingredient in baked goods to bolster antioxidant content. Practical Application: In order for Merlot grape seed flour (GSF) to be used in baking as a source of additional antioxidant compounds, the impact of heating on the polyphenolic compounds in the GSF needed to be examined. Thermal treatment of Merlot GSF caused significant decreases in the TPC, antioxidant power, and specific polyphenolic compounds when heated ≥180 °C. Thus while antioxidant content decreased with higher heating temperatures, this occurred at higher baking temperatures. Thus, GSF may be suitable for use as an ingredient in baked goods to bolster antioxidant content.     

均匀试验优化黑蒜提取液的抗氧化活性

以DPPH自由基清除率为指标,利用均匀试验考察了提取温度、时间、pH和底物质量比对黑蒜提取液抗氧化活性的影响.结果表明,pH对黑蒜提取液抗氧化活性具有显著影响(p0.05).黑蒜提取液制取的最佳工艺条件为:提取温度40℃,提取时间30 min,pH=3.0,黑蒜与去离子水的质量比(g∶mL)为1∶25,此时对DPPH自由基的清除率为92.65%,与理论值的相对误差3.59%.