Effect of Processing and Storage on Antioxidant Capacity of Honey

ABSTRACT: The impact of heat and filtration on the antioxidant capacity of clover and buckwheat honey during storage was analyzed. Processing clover honey did not significantly impact antioxidant capacity (determined by oxygen radical absorbance capacity [ORAC] assay); processing lowered the antioxidant capacity of buckwheat honey (33.4%). The antioxidant capacity of honeys was reduced after 6 mo of storage with no impact of storage temperature or container type detected at the end point of the storage period. Processed and raw clover honey antioxidant capacity decreased about 30%. Processed buckwheat honey decreased 24% in antioxidant capacity, whereas raw buckwheat honey decreased 49%. Antioxidant capacity of processed and raw honeys was similar after storage. Phenolic profiles, peroxide accumulation, 5-(hydroxymethyl)-2-furaldehyde (HMF), gluconic acid, and total phenolics were also analyzed. The impact of storage on antioxidant components of processed and raw honey was complex.     

油梨深加工的研究

一系列研究结果表明,油梨很适合与牛乳配合,经过乳酸发酵制成发酵油梨制品。将油梨果肉先于等量热水中热烫,再添加0.05%D-异抗坏血酸钠趁热打浆;预先将含11%全脂乳粉和2%脱脂乳粉的乳液加热至90℃,糖液加热至沸,然后按乳液中最终含8%蔗糖和8%～10%油梨果肉的比例,将糖液、油梨浆和乳液趁热混合搅打1min,5～8MPa均质,85～90℃、1min杀菌,并迅速冷却、接种乳酸菌,42～43℃下发酵4～4.5h,冷藏后熟,可制得色泽明亮(乳黄),滋味协调,口感均匀、细腻,无苦味,品质稳定的油梨酸乳。该工艺巧妙地避开了对油梨的强热处理,解决了防褐变和抑苦味的问题,方法简便易行,为解决油梨加工的瓶颈,带动油梨产业的发展开辟了1条新途径。     

Jam Processing Effect on Phenolics and Antioxidant Capacity in Anthocyanin-rich Fruits: Cherry, Plum, and Raspberry

ABSTRACT: Four cultivars of sour cherries (Balaton, Karneol, Kroeker and Northstar), 2 cultivars of plums (BY 8158.50 and Methley), and 1 red raspberry cv. Prelude were analyzed for total phenolics, antioxidant capacity, and total anthocyanins before and after jam production to evaluate their changes after thermal processing. Fruits had total phenolics ranging from 245.7 to 398.5 mg gallic acid equivalent (GAE)/100 g. Antioxidant capacity of fruits ranged from 354.8 to 692.3 mg/100 g, expressed as vitamin C equivalent antioxidant capacity (VCEAC). Total anthocyanins of fruits ranged from 30.9 to 67.1 mg cyanidin 3-glucoside equivalent (CGE)/100 g. In 100 g of jam, total phenolics varied from 132.9 to 218.9 mg GAE, while antioxidant capacity ranged from 205.6 to 373.5 mg/100 g VCEAC. Jams had total anthocyanins of 5.4 to 30.4 mg CGE/100 g. On the basis of fresh fruit (100 g), the processing and heating during jam making generally decreased the contents of total phenolics, VCEAC, and total anthocyanins. Major losses occurred in anthocyanin content where overall retention varied from 89% to 21%. HPLC analysis of individual anthocyanins from cherry cv. Balaton to its jam showed that processing caused 90% decrease in anthocyanins. The results indicated that more than 73% total phenolics and more than 65% antioxidant capacity were retained after processing fruits into jams. Optimization of food processing would help to conserve the bioactive phenolic compounds in fruits.     

Flavonoids and Antioxidant Capacity of Various Cabbage Genotypes at Juvenile Stage

ABSTRACT: Ten fresh cabbage genotypes ( Brassica oleraceavar capitata ) representing fresh-market, processing, and storage types were evaluated for total phenols, antioxidant capacity, and flavonoids at the 3-wk juvenile stage, at which time plants are uniform in size when grown under identical soil and environmental conditions. The genotypes studied, 'Bobcat,'Fresco,'Little Rock,'Marvelon,'Rinda,'Ramada,'Transam,'Genesee,'Huron,' and 'Octoking,' showed significant variations in concentration of phenolic phytochemicals and antioxidant capacity. Total phenols ranged from 110.2 mg gallic acid equivalents/100g in 'Genesee' to 153.3 mg gallic acid equivalents/100 g in 'Bobcat'. Total antioxidant capacity varied from 108.4 to 176.1 mg vitamin C equivalents/100 g, and flavonoids from nondetectable to 2.61 mg quercetin/100 g and from 1.30 to 7.03 mgkaempferol/100 g. Apigenin, luteolin, and myricetin were not detected. Five nutritional soil supplements from agricultural and food processing sources (quer-cetin flavonoid complex, commercial vegetable juice, crushed onion, crushed garlic, and green tea) were added to the cabbage genotype 'Rinda' once a week for 3 wk to assess their efficacy in increasing phenolic concentrations in cabbage leaves. Addition of the supplements generally resulted in increased levels of total phenols (97% with commercial vegetable juice), antioxidant capacity (41% with crushed onion), and quercetin plus kaempferol (110% with commercial vegetable juice) in the juvenile 'Rinda' plants with no significant increase with the addition of green tea. Nutritional soil supplements could provide enhanced levels of bioactive phenolic compounds as antioxidants in cabbage and therefore to consumers.     

烹调对常见蔬菜抗氧化活性与成分的影响

对常见的21种蔬菜,以爆炒、炖煮、微波3种烹调方法处理,采用相关方法测定比较其烹调前后的抗氧化活性,以及VC、总多酚及总类黄酮含量,比较不同烹调方法对蔬菜抗氧化活性及相关物质含量的影响,为评价人群实际抗氧化物质摄入量及相关研究提供参考.结果表明:炖煮导致蔬菜抗氧化活性及相关物质损失较多,微波及爆炒损失较少,且有部分指标出现了增加现象.     

牛油果中植物甾醇的鉴定及抗氧化、抑菌活性

以牛油果为原料,采用皂化法提取牛油果中植物甾醇,并对牛油果中植物甾醇种类、含量、抗氧化活性及抑菌活性进行分析研究。采用气相色谱-串联质谱联用法鉴定出牛油果中4?种主要植物甾醇：β-谷甾醇、菜油甾醇、胆固醇、豆甾醇,其含量分别为59.47、30.36、15.34、2.72?mg/100?g。以VE为对照,测定并分析了牛油果中植物甾醇对自由基（1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基、羟自由基（·OH）及超氧阴离子自由基（O2－·））的清除能力。植物甾醇对DPPH自由基、·OH、O2－·具有明显的清除效果,半数抑制浓度分别为6.82、35.92、17.08?μg/mL。采用抑菌圈法分析了甾醇粗提物对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌和沙门氏菌的抑菌活性。抑制作用强度依次为枯草芽孢杆菌＞金黄色葡萄球菌＞沙门氏菌＞大肠杆菌,表明牛油果植物甾醇具有较好的抑菌活性。     

不同加工工艺对蒲公英叶茶品质及抗氧化活性的影响

以蒲公英叶为研究对象,分别利用传统工艺、渥堆发酵以及添加β-葡萄糖苷酶发酵工艺加工成蒲公英绿茶和红茶,并通过汤色色差评价、功能性成分定量分析、香气组分分析、抗氧化能力分析以及感官评价,以期确定蒲公英叶茶加工的最佳工艺。经过β-葡萄糖苷酶发酵的蒲公英叶茶能获得较佳的汤色品质,未经过发酵工艺的蒲公英绿茶能保留较高的黄酮、多糖以及蛋白质成分,分别为1.42%、7.23%以及1.81%。未添加β-葡萄糖苷酶渥堆发酵的蒲公英红茶含有最多嗅感化合物,包括糠醇、5-甲基呋喃醛、大茴香醛、乙酸甲酯、苯乙酸甲酯、2-乙基丁酸、2-甲基四氢呋喃-3-酮、2,3-辛二酮等18种特有香气物质,主要表现为甜香、山楂、可可、肉类、爆米花等令人愉快的香气,为其获得较高感官评价香气评分奠定了物质基础,且其总抗氧化能力、DPPH清除率以及羟基自由基清除率分别为3.87 mmol/L FeSO₄·7H₂O、73.99%和34.21%,具有显著性的抗氧化能力。不同加工工艺制作的蒲公英叶茶品质及抗氧化活性存在差异性,其中渥堆发酵工艺较为适合蒲公英叶茶的制作。     

评价方法对层孔菌抗氧化能力的影响

评价层孔菌体外抗氧化能力和分析对抗氧化能力起重要贡献的活性物质。采用多种抗氧化测定方法测定不同层孔菌抗氧化活性,测定多糖、黄酮、总酚等抗氧化活性物质质量浓度,比较抗氧化活性物质质量浓度间、抗氧化测定方法间以及抗氧化测定方法与活性物质质量浓度间的相关性。结果表明,ws2和ws7具有较高的多糖、黄酮及总酚质量浓度,且不同基因型及相同基因型菌株活性物质质量浓度间相关系数差异较大;ws2和ws7有较强的羟自由基、DPPH、超氧阴离子自由基清除能力及较高铁离子螯合能力和还原力,不同抗氧化能力检测方法所得的结果具有不同的统计学相关性;总酚与不同抗氧化检测方法间均有较强的相关性,黄酮相关性次之,粗多糖与其相关性较低,因此,酚类物质对抗氧化能力贡献最大。     

肉桂醛熏蒸处理对香菇采后抗氧化能力及多胺的影响

为探究肉桂醛熏蒸处理对香菇采后抗氧化能力和多胺的影响,本研究以‘香菇808’品种为材料,采用不同浓度（0、8、40、80?nmol/L）的肉桂醛（溶剂为体积分数30%乙醇溶液）进行熏蒸处理。通过测定总酚含量、抗坏血酸（ascorbic acid,AsA）含量、抗坏血酸过氧化物酶（ascorbate peroxidase,APX）活力、过氧化氢酶（catalase,CAT）活力、超氧化物歧化酶（superoxide dismutase,SOD）活力、谷胱甘肽还原酶（glutathione reductase,GR）活力、2,2’-联氮-二(3-乙基苯并噻唑-6-磺酸)（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS）阳离子自由基清除能力、总抗氧化能力及游离态多胺含量指标,评价肉桂醛熏蒸处理的效果。结果表明：在4?℃低温下贮藏30?d后,各浓度肉桂醛熏蒸处理组的香菇抗氧化物酶（APX、CAT、SOD、GR）活力、ABTS阳离子自由基清除能力和总抗氧化能力均高于对照组,其中,40?nmol/L的肉桂醛熏蒸处理的效果最佳,但肉桂醛处理对总酚含量无明显影响。此外,各肉桂醛熏蒸处理组的游离态腐胺含量高于对照组,而游离态亚精胺、游离态精胺含量低于对照组。由此可知,肉桂醛熏蒸处理能够很好地提高香菇的抗氧化性及抗逆性,该研究结果为肉桂醛熏蒸处理在控制果蔬褐变和保鲜方面的应用提供了一定科学依据。     

真空冷冻干燥法制备高纯度低聚果糖工艺的初步研究

由于高纯度低聚果糖(P-FOS)有受热容易降解的特性,选择使用冷冻干燥法对高纯纯度低聚果糖进行干燥试验。试验测得P-FOS的共晶点-32℃,共融点-26℃,并通过单因素试验确定出适宜的干燥工艺条件为:冷阱温度-50℃,预冷冻速率为12℃/h,时间为5～6h,辐射加热温度为40～55℃,真空度为550～600Pa,干燥周期10～16h,得到片状的P-FOS,经加工得到P-FOS干粉产品。     

香辛料的抗氧化活性及对肉制品中杂环胺的影响

香辛料是一种重要的天然食品添加剂,被广泛应用于食品加工业中。大量研究表明:香辛料不仅具有增香和着色的效果,其中丰富的抗氧化活性成分还具有延长食品保质期的功效。作者综述了香辛料中的功能性成分,介绍了香辛料的抗氧化特性及其对肉制品中杂环胺类危害物生成的影响,为香辛料的抗氧化效应在肉制品加工过程中的安全控制应用提供参考。     

蒸汽爆破预处理对籽粒苋籽实抗氧化能力的影响

实验选取汽爆压力0.3、0.6、0.9、1.2、1.5 MPa,汽爆时间10、20、30、60、120 s,对籽粒苋籽实进行预处理。分别测定汽爆前后各组样品的总酚、总黄酮含量,并通过测定其对DPPH、ABTS⁺自由基的清除率、铁离子还原能力来衡量各组样品的抗氧化能力,旨在探讨蒸汽爆破对籽粒苋籽实总酚、总黄酮和抗氧化能力的影响。结果表明:经过汽爆处理,籽粒苋籽实总酚、总黄酮含量和抗氧化能力显著提高(p<0.5)。0.6 MPa、60 s是最佳处理条件,此时总酚、总黄酮含量分别为未汽爆组的5.3倍和7.3倍,DPPH、ABTS⁺自由基清除率、铁离子还原能力分别是未汽爆组的4.6、3.8和11.6倍。蒸汽爆破是一种高效、无污染的前处理方式,为籽粒苋籽实的后续开发奠定基础。     

Effect of Heat Treatment on Antioxidant Capacity and Flavor Volatiles of Mead

ABSTRACT: The objective of this study was to evaluate the effects of heat processing on the antioxidant capacity of mead (honey wine). Soy and buckwheat honey musts were subjected to 2 heat treatments and fermented into wine. Total phenolic concentration was determined. High-performance liquid chromatography (HPLC) phenolic profiling was performed on the methanol fraction of Amberlite extraction. Antioxidant capacity was evaluated using the oxygen radical absorbance capacity (ORAC) assay. Changes in volatile components were evaluated by headspace-solid phase microextraction/gas chromatography-mass spectrometry (H-SPME/GC-MS). ORAC values of experimental meads (3.62 m M Trolox equivalent) were comparable to those of commercial white wine (3.66 m M Trolox equivalent). No significant difference in antioxidant capacity due to heat treatment or honey type was observed. There was no difference in total phenolics between heat treatments in buckwheat mead; however, soy mead made from high-heated must had significantly greater phenolic concentration than the gently heated mead (α= 0.05). Linear regression analysis indicated a strong positive correlation between total phenolic concentration and antioxidant capacity by ORAC ( r = 0.9077; P < 0.0001). HPLC analysis of phenolic profiles in the methanol fractions of Amberlite extraction of the meads indicated significantly higher levels of certain phenolics as a result of the high-heat process in buckwheat mead, but not in soy mead. Differences in volatile components that potentially impact flavor were noted between high and low heat treatments. Results of this study suggest dramatic heat treatments that are often avoided because their flavor impact in mead production have the potential to alter the antioxidant capacity of mead by changing phenolic profiles.