Extraction and application of antioxidants from black glutinous rice

This research aimed to determine optimum extraction condition of black glutinous rice crude extract and to determine its application as an antioxidant in fish oil enriched mayonnaise. Black glutinous rice flour was extracted twice with 70:30 acetone-water mixture (v/v) at pH 2 and 6.8 for 2, 4 and 8 h of total extraction times. Total phenolic content (TPC), total monomeric anthocyanin content (TMA) and antioxidant activities as determined by ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity assays of the crude extracts were measured. The extraction with pH 6.8 solvent for 4 h yielded the crude extract with significantly highest antioxidant activities analyzed by both FRAP and DPPH tests (p ≤ 0.05) although its TPC and TMA were not greatest. The freeze-dried extract from this condition was then added into fish oil enriched mayonnaise at 500 mg/kg and 1000 mg/kg (oil weight basis). Conjugated diene hydroperoxides (CDH), thiobarbituric acid reactive substance (TBARs) and color in CIELAB system of the mayonnaise samples stored at 30 °C were determined up to 30 days. The samples contained 1000 mg/kg crude extract had lowest rate of CDH and TBARs increase but had greatest extent of color deterioration, possibly due to anthocyanin degradation and Maillard reaction.     

Hepatoprotective and antioxidant activity of anthocyanins in black rice bran on carbon tetrachloride-induced liver injury in mice

The benefits of anthocyanin-rich black rice bran extract (ARBE) on the liver of carbon tetrachloride (CCl₄)-intoxicated mice was investigated. Based on the in vivo experiment, the effect of cyanidin-3-glucoside (Cy-3-G) and peonidin-3-glucoside (Pn-3-G), the predominant anthocyanins in ARBE, on CCl₄ insulted hepatocytes L-02 was further evaluated. Mice treated with ARBE for 7 weeks by oral administration showed reduced aminotransferase activities in serum, accompanied by enhanced superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, while tiobarbituric acid reactive substances (TBARS), and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels were significantly decreased compared to CCl₄-intoxicated model group. Histopathological observation showed ARBE administration alleviated the pathological changes in livers of CCl₄-intoxicated mice. Similarly, preincubation of L-02 cells with Cy-3-G or Pn-3-G significantly alleviated CCl₄-induced injury dose-dependently, exhibited higher cell viability, decreased aminotransferase activity and enhanced cellular antioxidant status. Furthermore, Cy-3-G showed much stronger hepatoprotective activity than Pn-3-G at the same concentration. HPLC analysis showed that Cy-3-G accounted for more than 88% of total anthocyanins in ARBE. These results indicate that ARBE is significantly beneficial to liver health, and that Cy-3-G is the predominant anthocyanin in ARBE exerting this effect. The antioxidant activity of anthocyanins is an important mechanism by which ARBE exerts hepatic health benefit.     

维生素E抗油脂氧化的功能探讨

抗氧化功能是维生素Ｅ的一种基本功能。维生素Ｅ特殊的化学结构与性质使得它既能抗油脂自动氧化，又具有一定的淬灭１Ｏ２的能力。本文根据目前公认的油脂氧化机理，就维生素Ｅ抗油脂氧化的机理与具体功能进行了探讨，并且介绍了一些常见油脂中的ＰＵＦＡ与维生素Ｅ的水平。     

复合黑米海带茶饮料的开发

以黑米为原料，加入海带、绿茶及稳定剂，研制天然黑米海带糊茶饮料的工艺流程及操作要点。     

Physicochemical and antioxidative properties of red and black rice varieties from Thailand,China and Sri Lanka

Nine red and three black rice varieties from Thailand, China and Sri Lanka were analysed to determine their proximate composition and their physicochemical and antioxidant properties. Four groups of rice varieties with different amylose contents were identified. Cyanidin 3-glucoside and peonoidin 3-glucoside were confirmed as the dominant anthocyanins in black rice varieties with contents ranging from 19.4 to 140.8 mg/100 g DM and 11.1–12.8 mg/100 g DM, respectively. Total phenolic content (TPC) differed significantly between the varieties, but not between the colours. Highest TPC was found in the red Thai rice Bahng Gawk (BG) with 691 FA equivalent mg/100 g DM, which showed as well the highest antioxidant properties. In red varieties, the major phenolic acids in the free form were ferulic, protocatechuic and vanillic acid, whereas in black varieties protocatechuic acid was dominant followed by vanillic and ferulic acid. In the bound form, ferulic acid was predominant in both colours, where contents differed significantly, followed by p-coumaric and vanillic acid. The antioxidative capacity did not differ significantly between both colours but amongst genotypes. Antioxidant capacity of rice varieties ranged within 0.9–8.1 mmol Fe(II)/100 g DM for FRAP and 2.1–12.3 mmol TEAC/100 g DM. DPPH scavenging ability ranged from 13.0% to 76.4% remaining DPPH.     

不同极性抗氧化剂在猪油和猪油乳浊液中的抗氧化活性

四种食品抗氧化剂—维生素E(VE或α-生育酚)、茶多酚(TP)、二丁基羟基甲苯(BHT)、特丁基对本二酚(TBHQ)分别添加到猪油、猪油+司班80和猪油+司班80+水为基质的七种不同的体系中,置于(65±1)℃的条件下贮存,每三天对其过氧化值(POV)进行分析,并比较四种不同极性抗氧化剂分别在这七种体系中的抗氧化活性结果表明:在纯猪油体系中TBHQ活性最强,抗氧化效果最好,其次为BHT,再其次为TP,而VE的活性最弱在含有乳化剂和水的猪油体系及只含有乳化剂的猪油体系中,BHT的活性最强体系中的＊,’“起到催化氧化的作用,可加速其氧化,而柠檬酸则可有效钝化卜’”催化氧化活性,大大提高猪油的氧化稳定性     

Composition of industrial seedless black currant pomace

The aim of the work was to characterize the basic chemical composition including polyphenols of seedless industrial dried black currant pomace from two subsequent harvest seasons, 2006 and 2007. Pomace after removing seeds was separated into three fractions: with particles smaller than 0.8 mm, 2–5 mm and greater than 5 mm. The pomace was analyzed for dry substance, protein, fat, ash, total dietary fiber (TDF), soluble solids content, acidity, organic acids, saccharides and polyphenols. In addition, the antioxidant activity of the pomace was assayed by the DPPH method. All the fractions were characterized by a high content of total dietary fiber above 63% and a low content of saccharides below 3.15% and acidity below 3.2%. The composition of polyphenol compounds of all the fractions was qualitatively determined, yet it was shown that the fraction of the pomace of 2–5 mm is characterized by the greatest content of phytocompounds, of which anthocyanins constitute about 90% of the polyphenols determined. Moreover, the presence of myricetin and quercetin glycosides as well as considerable quantities of myricetin and quercetin aglycones was found in the pomace. The pomace had a high antioxidant activity ranging from 93.3 to 126.5 μM TEAC/g. It was also found that the content of most polyphenol compounds investigated, as well as protein, ash, TDF, acidity and saccharides, was statistically dependent on the type of fraction. Disclaimer: The views and opinions expressed in this publication are purely those of the writers and may not in any circumstances be regarded as stating an official of European Commission.     

Distribution of aflatoxins in shelling and milling fractions of naturally contaminated rice

The objective of this study was to determine the distribution of an economically important class of mycotoxins, the aflatoxins, in rice milling fractions. Rice plants grown under field production conditions are frequently infected with types of pathogenic fungi that produce toxic metabolites (mycotoxins). Paddy (seeds) rice from healthy plants in the field was collected and stored on a farm under humid, poorly ventilated conditions. Samples were milled into four fractions (hulls, brown rice, bran and white rice) and analysed for aflatoxins (B₁, B₂, G₁ and G₂) using a validated method. Rice fractions from healthy plants, which contained low levels of aflatoxins (less than 1?µg?kg^?1), were used to determine the efficiency of the extraction method. Seeds stored under poor conditions were found to be contaminated with aflatoxins B₁ and B₂ as were the fractions. The sums of AFB₁ and AFB₂ in stored paddy rice, hulls, brown rice, bran and white rice were 141, 39, 158, 367 and 56?µg?kg^?1, respectively. The ratio of aflatoxin B₁ and B₂ was about 10?:?1. AFG₁ and AFG₂ were less than 1?µg?kg^?1. Thus, brown rice contained 92.9% of the aflatoxins in paddy rice, whereas white rice contained only 27.9%.     

黑米花青苷胶囊体外清除自由基及抗氧化作用的研究

利用Fenton反应产生羟自由基、邻苯三酚在微碱条件下自氧化产生O-2、磷钼络合物法分别研究了黑米花青苷胶囊和黑米色素对羟基自由基、超氧阴离子的抑制和其总抗氧化活性。结果表明黑米花青苷胶囊和黑米色素能有效清除自由基,具有良好的抗氧化作用。其中黑米花青苷胶囊和黑米色素对羟自由基、超氧阴离子的抑制和其总抗氧化活性随着样品浓度增高而增加。黑米色素对羟自由基、超氧阴离子的抑制和总抗氧化活性显著高于黑米花青苷胶囊。     

Production of black rice cake using ground black rice and medium-grain brown rice

Puffed rice cakes were produced from a blend of ground black rice (GBR) and medium‐grain brown rice (GMBR) by using a rice cake machine. Effects of moisture content, heating temperature and heating time on quality of the black rice cake were investigated. The specific volume of black rice cakes showed an increasing trend with increasing tempering moisture, heating temperature and heating time. The hardness of puffed black rice cake decreased as tempering moisture and heating time increased, and was influenced more by GMBR content than heating temperature. In general, the black rice cake lightness and yellowness decreased steadily with increasing GBR content, while tempering moisture, heating temperature and heating time did not significantly affect the colours of black rice cake. On the contrary, the redness increased with increasing GBR contents. The weight loss during tumbling was not found at all puffing conditions.     

黑米乳酸菌醇化饮料的研究

研究了黑主乳酸菌醇化饮料。结果表明：依次减少牛奶用量的梯度培养达到了驯化乳酸菌菌种的目的，并且得出用驯化菌种和黄酒酵母发酵黑米乳酸菌醇化饮料的工艺条件：蔗糖添加量为2％，接种量为乳酸菌3％，活性黄酒酵母0．5％，发酵温度38℃，发酵时间7－8h。研制的黑米乳酸菌醇化饮料具有浓郁的乳酸和黄酒香味，组织均匀，酸甜醇味适度。     

Antioxidant activity and profiles of common fruits in Singapore

Thirty-eight types of fruits commonly consumed in Singapore were systematically analysed for their hydrophilic oxygen radical absorbance capacity (H-ORAC), total phenolic content (TPC), ascorbic acid (AA) and various lipophilic antioxidants. Antioxidant composition and concentration varied widely across different fruits. Many of the tropical fruits tested were high in antioxidants. Amongst all fruits tested, sapodilla (Manilkara zapota) had the highest H-ORAC and TPC whilst guava had the highest AA per gram fresh weight. Papaya, red watermelon and cantaloupe had the highest β-cryptoxanthin, lycopene and β-carotene per gram fresh weight, respectively. On the other hand, durian and mangosteen were high in tocopherols and tocotrienols, respectively. Based on consumption data, Chinese Singaporeans appear to have a higher intake of carotenoids and tocopherols rich fruits compared to the US population. As fruits are a rich source of diverse antioxidants, efforts to promote consumption of a variety of fruits should be continued for public health benefits.     

Antioxidant activity and profiles of common vegetables in Singapore

Sixty-six types of vegetables commonly consumed in Singapore were analysed for their hydrophilic oxygen radical absorbance capacity (H-ORAC), total phenolic content (TPC), ascorbic acid (AA) and various lipophilic antioxidants. A single batch analysis of each vegetable showed that antioxidant composition and concentration varied widely across different vegetables. The vegetables with intense colours typically have high H-ORAC, TPC, AA, and carotenoid contents. Vegetables unique to the Asian market such as matrimony vine (Lycium chinense Miller), coriander, Chinese kale, water spinach and red chilli were consistently ranked high in H-ORAC, TPC, carotenoids and vitamin E levels. Based on consumption data, Chinese Singaporeans appear to have a higher intake of lutein, zeaxanthin, β-carotene, and tocopherols compared to the US population. Overall findings suggest that dark green leafy and brightly-coloured vegetables tend to contain high antioxidants. Our data are useful reference and substantiate many public health agencies’ recommendation to consume more vegetables, particularly the dark green leafy and brightly-coloured varieties.     

杂交稻谷的碾米工艺特性的研究

对不同品种和不同性质的杂交稻谷及常规稻谷进行碾米工艺实验,比较了不同稻谷的砂辊碾米、铁辊碾米及砂辊-铁辊组合碾米的工艺特性,得到杂交稻谷及高爆腰率稻谷的最佳碾米工艺参数。     

Studies on freeze-withering in black tea manufacturing

In order to reduce the withering time during black tea manufacture, freeze-withering was attempted, which resulted in flaccid leaves with increased cell membrane permeability in a shorter period of time. The freeze-withered leaves had similar amounts of quality precursors as that of the conventionally withered leaves. The resultant black tea was better in quality than those manufactured without withering and after normal withering. Manufacturing of fresh leaves resulted in comparable levels of theaflavins, but the tea was not acceptable due to its harshness. Increased cell membrane permeability during freeze-withering showed that the leaf attained a sufficient degree of physical wither. The decreases in the levels of chlorophyll showed that chemical withering had also been achieved during freeze-withering, which is supported by the increased levels of caffeine.     

Antioxidants and proteins in ethylene-treated kiwifruits

Ethylene-treated kiwifruit (Actinidia deliciosa) cultivar ‘Hayward’ was compared with the air-treated one. The correlation coefficients between total polyphenols and the antioxidant capacities measured by [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS) with Trolox equivalent antioxidant capacity (TEAC), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), and cupric reducing antioxidant capacity (CUPRAC) assays for ethylene-treated kiwifruits were as followed: 0.74; 0.93 and 0.98, in comparison with air-treated samples of 0.72, 0.88 and 0.97, respectively. CUPRAC produced the most consistent measurements for ethylene-treated kiwifruit. In extracted and separated, by electrophoresis, kiwifruit proteins differences were found in the sodium dodecyl sulfate–protein bands, in the region of 32 kDa, in samples after the first days of treatment. Based on antioxidant activity and the protein profiles it can be concluded that the ethylene treatment shortened the ripening process of the fruits.     

Correlation of tocopherol,tocotrienol, γ-oryzanol and total polyphenol content in rice bran with different antioxidant capacity assays

The relationship between antioxidant capacity and levels of various antioxidants in rice bran and brown rice powder was evaluated. Three different varieties of Venezuelan rice, namely, Cimarrón, Zeta 15 and FONAIAP-1, were studied using ferric reducing antioxidant power (FRAP), 2,2′-azinobis-3-ethylbenzotiazoline-6-sulphonic acid (ABTS), and oxygen radical absorbance capacity (ORAC) to measure antioxidant capacity. The results showed that rice varieties contained different levels and combinations of total polyphenols, γ-oryzanol, α- and γ-tocopherols and α-, γ- and δ-tocotrienols. Compared to brown rice powder, rice bran contained most of the antioxidants and had correspondingly higher values of antioxidant capacity. Principal components analysis and multiple regression on the data indicate that FRAP was sensitive to polyphenols and total tocotrienols, while ORAC was sensitive to polyphenols and total tocopherols. ABTS was the least sensitive of all assays tested. Thus, results from antioxidant capacity assays must be interpreted with caution particularly in complex systems and that further study is necessary to define more precisely the nature of the relevant chemical reactions.     

黑米色素及黑米酒生产新工艺的研究

本文提出了以安徽特产黑米为原料,利用液化酶、糖化酶进行液化和糖化,利用蛋白酶进行蛋白质分解,利用活性干酵母进行酒精发酵生产黑米酒的一种新的生产方法,同时对原料黑米色素提取液和黑米酒色素进行了初步分析,并且讨论了新工艺生产的黑米酒色素的稳定性;考察了黑米色素与黑米酒色素分别在紫外光和可见光的吸收值,提出了黑米色素和黑色酒色素的最大吸收值的范围。     

Production of functional substances from black rice bran by its treatment in subcritical water

Black rice bran was treated by water and subcritical water at temperatures ranging from 20 to 260 °C for 5 min and at 200 and 260 °C for 5-120 min. The bran extracts were analyzed for their radical scavenging activity, protein and carbohydrate contents, molecular-mass distribution, antioxidation activity, emulsifying activity, and emulsion-stabilizing activity. The radical scavenging activity and the protein content of the extract were higher at higher treatment temperature. The carbohydrate content also increased with increasing temperature up to 200 °C, then steeply decreased at the temperatures higher than 200 °C. The bran extracts treated at 260 °C for 5 min exhibited a suppressive activity toward autoxidation of linoleic acid with the increasing the weight ratio of the bran extract to linoleic acid. The bran extracts prepared at 40-200 °C for 5 min showed the emulsifying- and emulsion-stabilizing activities, while the extracts prepared at 220-260 °C were low in the activities.