Maximizing phenolics, antioxidants and sensory acceptance of UV and ultrasound-treated peanuts

The effects of varying doses of UV and ultrasound (US), and incubation times at 25 °C on total phenolics (TP), antioxidant capacity by two methods, trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) and sensory overall acceptance (OA) of treated peanuts were investigated. Optimum process parameters for UV and US were determined using response surface methodology. UV and US increased TP, TEAC and ORAC total antioxidant capacity (TAC) of most treated peanuts, whereas OA decreased in all treatments compared to controls. US was more effective than UV in increasing total antioxidants. Optimum US process parameters at 36 h incubation time will result in products with TAC ≥ 68 μM TE/g, TP ≥ 1.51 mg GAE/g, TEAC ≥ 2.76 μM TE/g, and OA ≥ 5 or neither like nor dislike.     

Antioxidant properties and total phenolics content of green and black tea under different brewing conditions

 The antioxidant activity and the total phenolics content of various tea extracts were analysed. Green and black tea were brewed from 0.5 min up to 10 min under different brewing conditions (stirring the extract, chopping the tea leaves before brewing). For measuring the antioxidant activity, the Trolox equivalent antioxidant capacity (TEAC) test and the low density lipoprotein (LDL) oxidation test were used. In all cases the antioxidant activity as well as the content of the phenolics increased with the brewing time. In black tea (brewed without stirring or chopping), the total phenolics increased from 33.8 mg/100 ml after 0.5 min up to 68.4 mg/100 ml after 10 min brewing time. Stirring during brewing led to higher phenolic yields in the extract. Thus, phenolics in stirred black tea ranged from 44.5 mg/100 ml (0.5 min) to 96.7 mg/100 ml (10 min). Chopping the tea leaves resulted in the highest content of phenolics. Antioxidant activity was well correlated with the corresponding total phenolics content. The results of the LDL oxidation test varied more than those of the TEAC test. Received: 27 May 1998 / Revised version: 15 July 1998     

Tocopherols and tocotrienols as free radical-scavengers in refined vegetable oils and their stability during deep-fat frying

The aim of this study was to assess the effect of total tocopherols and tocotrienols of refined vegetable oils on oil radical-scavenging activity and to investigate the stability of the various homologues during the deep-fat frying of French fries. Eight different refined vegetable oils were investigated, having variable levels of natural tocopherols and tocotrienols. A direct correlation between the radical-scavenging capacity of the oils, measured by the DPPH test, and the total content of natural tocopherols and tocotrienols was found. Frying experiments showed that the stability of the different tocopherols and tocotrienols present in the refined vegetable oils basically depend on two factors: the fatty acid composition of the oil, in particular polyunsaturated fatty acid content, and the kind of tocopherol and tocotrienol homologues present. The more oxidizable the oil, on the basis of fatty acid composition, the more stable were the tocopherolic antioxidants. Among the different homologues, γ-tocotrienol in palm super olein proved to be the least stable during the deep-fat frying, thus preserving the other homologues.     

不同品种蓝莓酒抗氧化能力及其多酚含量分析

本实验对6个不同品种的蓝莓酒的总酚、总类黄酮、原花青素、总花色苷和总抗氧化能力及其相关性进行了分析,结果发现,不同品种的总酚、总类黄酮、原花青素、总花色苷和总抗氧化能力变幅和变异系数较大,存在显著差异(p＜0.05);蓝莓酒总抗氧化能力与总酚、总类黄酮、原花青素和总花色苷含量之间存在显著性的相关性(p＜0.01),其中与原花青素的相关性最强,达到0.898.     

Comparison of the effects of different types of soya milk on the total antioxidant capacity of black tea infusions

Experimental evidence has shown that the polyphenols in black tea exhibit strong antioxidant potential in vitro and in vivo. The objective of the present study was to analyse and compare the total antioxidant capacity (TAC) of five brands of tea and to evaluate whether the addition of different varieties of soya milk decreased the TAC compared to semi-skimmed bovine milk. Each of the teas analysed was a significant source of antioxidants (7796–10,434 μmol/l FRAP). The addition of milk lowered the TAC of each of the teas analysed. When compared to tea with semi-skimmed bovine milk, each of the five teas analysed had either significantly higher antioxidant values or no change after the addition of soya milk. The addition of soya milk to black tea may be a useful alternative to semi-skimmed bovine milk if wishing to maintain the overall antioxidant potential of the tea infusion.     

Anthocyanins profile,total phenolics and antioxidant activity of black currant ethanolic extracts as influenced by genotype and ethanol concentration

Ethanolic extracts prepared from the fruits of three cultivars of black currant (‘Record’, ‘Blackdown’ and ‘Ronix’) macerated in three concentrations (40%, 60% and 96%) of aqueous ethanol were investigated for their anthocyanins profile, total phenolics and antioxidant activity.     

Effect of jam processing and storage on total phenolics, antioxidant activity, and anthocyanins of different fruits

BACKGROUND: Fruits have been widely recognised as an excellent source of bioactive phenolic compounds. The purpose of this study was to evaluate the effect of jam processing of strawberry, cherry, apricot, fig and orange on the total phenolics, antioxidant activity and anthocyanins during 5 months of storage at 25 °C. RESULTS: Fresh strawberry had the highest contents of total phenolics (8503.1 mg GAE kg^?1) followed by cherry, apricot, fig and orange, respectively. Jam processing decreased the total phenolics, antioxidant activity, and anthocyanins of all fruits. Total phenolics of jam during storage decreased only in apricot, fig and orange. Fresh strawberry had the highest antioxidant activity (54.88% inhibition) followed by the other fruits. Antioxidant activity did not change in strawberry during jam storage, while there are reductions in the other fruits were observed. Fresh strawberry had the highest anthocyanins (2323.8 mg cya‐3‐glu kg^?1), followed by cherry and the other fruits, respectively. Results showed only a decrease of anthocyanins and pH in apricot and fig jams during 5 months of storage. CONCLUSION: Despite the reduction of these compounds in jam processing, it is considered a good method to maintain them during 5 months of storage. Copyright © 2011 Society of Chemical Industry     

Processing‐induced changes in total phenolics and procyanidins in clingstone peaches

Clingstone peaches contain a wide array of complex secondary plant metabolites and polyphenolics, and increasing evidence indicates that many of these components are important in human health. Oligomeric flavan‐3‐ol metabolites (procyanidins) are particularly interesting owing to their potent antioxidant activity and protective cardiovascular effects. To date, little information is available on how postharvest and processing conditions impact levels of phenolics and procyanidins in fruit. This research addresses the impact of lye peeling, freezing, storage temperature (4 and 30 °C) and three different time–temperature sterilisation combinations on levels of total phenolics (TPs) in Ross clingstone peaches. Additionally, we describe the profile of procyanidin oligomers (monomers through heptamers) in clingstone and freestone peaches and demonstrate a dramatic decrease in procyanidins in thermally processed peaches. TP levels ranged between 316 and 397 mg kg^?1 in peeled peaches and between 376 and 609 mg kg^?1 in unpeeled peaches. Cold storage at 4 °C for 14 days or freezing and storing at ?12 °C for 3 months produced no loss in TPs. Peaches stored at 30 °C for 24 h resulted in a 1.7‐fold increase in TPs. Studies of TPs in peaches processed at temperatures of 213 °F for 40 min, 220 °F for 10 min and 230 °F for 2.4 min indicate that processing above 213 °F decreases levels of both TPs (up to 21%) and procyanidins (up to 100%). Processing at 213 °F for 40 min produced no significant loss in TPs. Furthermore, studies reveal that a 30–43% loss in phenolic levels occurs during the first 3 months in storage after canning. It is clear that both storage and thermal processing conditions profoundly impact the levels of polyphenolics in peaches. More interestingly, these studies indicate that peaches are a rich source of procyanidins, having profiles similar to those found in cocoa, apples, wine and tea. © 2002 Society of Chemical Industry     

Antioxidant capacity and total phenolics of <Emphasis Type="Italic">Cyphostemma digitatum</Emphasis> before and after processing: use of different assays

In the framework of standardisation of new healthy food sources, this paper aimed to study the total phenolics and the antioxidant power of Cyphostemma digitatum (Vitaceae) in water and ethanol extracts, using 96-well micro plates with BMG FLUOstar Optima micro plate reader. Total phenolics by Folin–Ciocalteu method in the water extracts were significantly lower after processing, decreasing from 1.41 ± 0.06 g GAE/100 g in the raw leaves to 0.80 ± 0.08 g GAE/100 g in the processed sample; the ethanol extract revealed the same trend with higher values, decreasing from 1.95 ± 0.03 to 1.56 ± 0.12 g GAE/100 g. The antioxidant capacity was elucidated by four methods: TEAC, DPPH, FRAP and ORAC. No or very weak correlations were found between antioxidant assays and total phenolics; this confirms that the antioxidant capacity could be attributed to other molecules. The ORAC assay proved to be more powerful than the other assays; it showed 103.3 ± 2.5 mmol/100 g Trolox equivalents in the raw leaves ethanol extract and 91.9 ± 3.0 mmol/100 g in the processed sample. ORAC assay showed the opposite for the water extract where the antioxidant capacity increased from 16.7 ± 0.2 to 41.7 ± 2.7 mmol/100 g Trolox equivalents after processing, which could be attributed to new water-soluble compounds generated in the consumed form.     

固态发酵法脱除菜籽饼粕中总酚及芥子碱的工艺研究

筛选出能高效降解菜粕中总酚及芥子碱的菌株,并进行混合发酵,研究了不同菌株、不同菜粕原料、不同接种量、不同发酵时间、不同营养源及不同金属离子对总酚及芥子碱降解率的影响。结果表明:酿酒酵母、纳豆芽孢杆菌及枯草芽孢杆菌B4以8%的总接种量,等比例接种到添加了5%糖蜜和0.05%的硫酸铜及硫酸亚铁的菜籽饼粕(含水量为50%)中,发酵72h,菜粕中的总酚和芥子碱降解率可达到70.72%及80.06%。     

Changes in physio-biochemical metabolism,phenolics and antioxidant capacity of different Chinese pea varieties during germination

In this study, changes in physiological and biochemical metabolism, phenolics and antioxidant capacity of six different Chinese pea varieties during germination were investigated. Results showed that germination had a positive effect on the physiological indexes and bioactive substances of pea. The bud length, root length, fresh weight and respiration rate of pea sprouts increased with germination time. The content of free and bound phenolics in germinated peas increased significantly. Meanwhile, activated phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H) and 4-coumaric acid coenzyme A ligase (4CL) led to the accumulation of phenolics. Antioxidant capacity of pea sprouts increased with the extension of germination time. From the perspective of principal component analysis, compared with the other five varieties, Longwan 7 can be distinguished by free phenolic content in the later stage of germination. The result provides a new perspective for further development of pea as a functional food for human consumption.     

Comparing profiles and antioxidant properties of soluble and insoluble phenolics in Perilla frutescens seed flour extracts obtained by different extraction/hydrolysis methods

Cold‐pressed Perilla frutescens seed flour (CP‐PFSF) is a potential source of natural antioxidants. In this study, different methods were used to extract both soluble and insoluble phenolics from CP‐PFSF. Also, the phenolic profiles and antioxidant properties were compared. Results showed that soluble phenolics could be extracted using aqueous‐organic solvents, where 80% acetone resulted in the highest extraction yield and antioxidant activities. Insoluble phenolics remaining in residues could be released by acid or alkaline hydrolysis, where acid hydrolysis provided higher yield and antioxidant activities than alkaline. Soluble and insoluble phenolics could be extracted simultaneously through acid/alkaline hydrolysis, resulting in nearly the same yields for total phenolics. However, the phenolic components and antioxidant activities of extracts varied significantly, depending on the methods. Principal component analysis and correlation analysis revealed that a strategy of 80% acetone with successive acid hydrolysis steps released more rosmarinic acid, which have high antioxidant activities.     

Daily consumption of phenolics and total antioxidant capacity from fruit and vegetables in the American diet

The daily intake of total phenolics, total flavonoids and antioxidants in the American diet was estimated from the most common 34 fresh fruit and vegetables and their daily consumption data. Among 14 fruit and 20 vegetables, orange contributed the highest amount of total phenolics [117.1 mg gallic acid equivalent (GAE) person^?1 day^?1] and antioxidants [146.6 mg vitamin C equivalents (VCE) person^?1 day^?1]. Orange contributed about 26 and 25% of total phenolics and antioxidant, respectively, in the daily consumption of fruit and vegetables. Apples showed relatively high levels of total phenolics and antioxidant capacity comparable to those of oranges and their phenolics and antioxidants contribution is the second highest. Even though potatoes had lower levels of phenolics and antioxidant capacity, they were third due to the fact that their consumption is the highest (137.9 lb person^?1 year^?1) in the American diet. Although plums and strawberries were ranked as the group with the highest total phenolics and antioxidant capacity among 34 tested fruit and vegetables, their contributions were relatively low due to their lower daily consumption. Generally, the levels of total phenolics, total flavonoids and antioxidant capacity of fruits were higher than those of vegetables. American daily intake of phenolics, flavonoids and antioxidants from fruits and vegetables was estimated to be 450 mg GAE, 103 mg catechin equivalents and 591 mg VCE, respectively. Although we do not yet know the required minimum daily amounts of antioxidants, when we estimate the daily requirement of antioxidants, we must consider not only the antioxidant concentrations of the particular food, but also the daily intakes of the food. Copyright © 2005 Society of Chemical Industry     

The phenolic profiles and antioxidant activity in different types of tea

Phenolics are suggested to be the major bioactive compounds responsible for the health benefits of tea. Seven types of tea were extracted using boiling water. The extraction kinetics was investigated. To more fully characterise the antioxidant profiles and possible associated health benefits of these tea types, the total water‐soluble solid content, phenolics, flavonoids, and antioxidant and antiproliferative activities were quantified. Green tea leaves (GTL) were found to have the highest phenolic content (128.7 ± 1.7 mg g^?1, P < 0.05), followed by teas of decaffeinated green tea bag (dGTB), green tea bag (GTB), black tea bag (BTB), decaffeinated BTB, black tea leaves and oolong tea leaves (OTL). Among the three leaf teas, GT displayed the greatest antioxidant activity (4850.2 ± 60.7 μmol g^?1, P < 0.05), followed by black tea (BT) and oolong tea (OT). As for the four bag teas, decaffeinated GT possessed the strongest antioxidant activity (4431.1 ± 335.0 μmol g^?1, P < 0.05), followed by GT, BT and decaffeinated BT. The results display that phenolic/flavonoid content well correlated with antioxidant activity. Proliferation of three human cancer cells was significantly inhibited in a dose‐dependent manner after exposure to some tea extracts. This may influence consumers in selecting the type of tea and tea brewing times, exhibiting greater health benefits.     

Free-radical-scavenging activity and total phenols of noni (Morinda citrifolia L.) juice and powder in processing and storage

The fresh juice of noni (Morinda citrifolia L.), a tropical plant used as a folk medicine in Pacific islands, possessed free-radical-scavenging activity (RSA), 1,1-diphenyl-2-picrylhydrazyl (DPPH), at 140 mg equivalent ascorbic acid/100 ml and total phenols at 210 mg gallic acid/100 ml. Fermentation of noni fruit for 3 months resulted in a loss of more than 90% of RSA. Dehydration at 50 °C produced a loss of 20% of RSA. Storage of fresh noni juice at 24 °C for 3 months reduced RSA more than 90%. Storage of noni juice or powder at −18 °C and 4 °C for 3 months decreased RSA by 10–55%. The reduction of RSA of noni juice or purée during heat treatment or dehydration was much greater than reduction of total phenols. For maintenance of the substantial antioxidant properties of noni products, processing of noni powder or fresh frozen noni juice rather than fermented noni juice is recommended.     

Vitamin C,total phenolics and antioxidative activity in tip‐cut green beans (Phaseolus vulgaris) and swede rods (Brassica napus var. napobrassica) processed by methods used in catering

BACKGROUND: Retention of nutrients in vegetables during blanching/freezing, cooking and warm‐holding is crucial in the preparation of both standard and therapeutic diets. In the present study, conventional cooking in water, and cooking by pouch technology (boil‐in‐bag, sous vide) were compared in their ability to retain vitamin C, total phenolics and antioxidative activity (DPPH and FRAP) in industrially blanched/frozen tip‐cut green beans and swede rods. RESULTS: After conventional cooking, 50.4% total ascorbic acid, 76.7% total phenolics, 55.7% DPPH and 59.0% FRAP were recovered in the drained beans. After boil‐in‐bag cooking, significantly (P < 0.05) higher recoveries were obtained, i.e. 80.5% total ascorbic acid, 89.2% total phenolics, 94.8% DPPH and 92.9% FRAP. Recoveries after sous vide cooking were comparable to those of boil‐in‐bag cooking. By conventional cooking, 13.5–42.8% of the nutrients leaked into the cooking water; by sous vide about 10% leaked to the exuded liquid, while no leakage occurred by boil‐in‐bag cooking. Warm‐holding beans after cooking reduced recoveries in all components. Recoveries in swede rods were comparable but overall slightly lower. CONCLUSION: Industrially blanched/frozen vegetables should preferably be cooked by pouch technology, rather than conventional cooking in water. Including cooking water or exuded liquid into the final dish will increase the level of nutrients in a meal. Warm‐holding of vegetables after cooking should be avoided. Copyright © 2010 Society of Chemical Industry     

两种不同检测方法分析不同类型天然和人工染菌食品中菌落总数的比较研究

目的：验证分析测试片检测不同类型食品菌落总数计数的适用性。 方法：与传统国标平板计数方法平行比较,应用测试片检测肉制品、面食、冷饮、奶制品、豆制品、果蔬和坚果7大类70份天然食品,以及以最常见的两种食源性微生物金黄色葡萄球菌和大肠埃希菌作为标准菌株,制备22的份不同食品基质的人工染菌样品。所有检测结果使用两种不同数据方法进行处理分析,以此探讨不同方法检测结果的相关性。 结果：依据ISO 16140-2 2016推荐的数据处理分析方法发现测试片和国标平板计数方法检测不同类型天然和人工染菌食品样品的菌落总数结果对数值差值的平均值均小于0.5;同时、单因素方差分析结果也证实两种方法检测结果无显著性差异（P>0.05）,相关系数高达0.938,不同方法检测结果之间呈正相关。以此发现本研究随机选择食品中菌落总数最高的分别为豆沙春卷、京酱肉丝和鲜猪皮。 结论：本研究证实测试片对不同类型食品菌落总数检测结果与国标平板计数方法结果一致性好,并且具有简单、快捷、易于标准化的优点,适用于不同层级食品承检机构。     

基于测试片法与平板计数法对不同类型食品中菌落总数结果的比较分析

目的比较菌落测试片法与平板计数法在不同类型食品中菌落总数测定结果的差异。方法在市面上随机抽取生肉制品、鲜奶制品、豆制品、粮食制品、冷冻饮品、坚果籽实、即食果蔬制品共112批,同时按菌落测试片法和平板计数法进行菌落总数测定,并对计数结果进行统计学分析。结果菌落测试片法与平板计数法的测定结果对数值差值的平均值|d log|= 0.06(<0.5),配对t检验P=0.860(>0.05)。结论菌落测试片法与平板计数法对上述7种类型的食品菌落总数测定结果无显著性差异,菌落测试片法可用于上述食品的菌落总数测定。