High Temperature Storage Effect on Longevity of Rice Seeds

Storage of Indica (Oryza sativa L. cv. Katakutara) and Japonica (Oryza sativa L. cv. Kusabue) rice seeds at 30° and 40°C for 2 months in the dark did not result in the loss of viability in both cultivars. Storage at 60°C, however, resulted in a complete loss of germination after 45 days in the case of Kusabue while the Katakutara rice seeds retained the germination potential well above 95%. Corresponding increases in the linoleic acid content of the free fatty acid fraction and TBA values of the extracted lipid fraction were also observed in Kusabue rice seeds. The investigation indicated that the Indica rice seeds were better protected than the Japonica rice seeds by the enclosing rice hull during the storage period.     

糙米体外消化过程中酚类物质含量及抗氧化活性

以糙米为对象,围绕其体外消化过程酚类物质及抗氧化活性变化开展研究。结果表明：粳型糙米中总酚含量显著高于籼型糙米（约1.5?倍）。胃和小肠消化显著促进粳型和籼型糙米中酚类物质释放（P＜0.05）,其释放量（以没食子酸当量计）最高值为460.9?mg/100?g和401.1?mg/100?g,粳型糙米中酚类物质释放量显著高于籼型糙米;两者酚类物质释放量随消化时间变化趋势均符合幂函数模型。铁离子还原/抗氧化能力（ferric-reducing antioxidant power,FRAP）和氧自由基清除能力（oxygen radical absorbance capacity,ORAC）实验表明糙米体外消化过程中释放的酚类物质具有良好抗氧化能力,粳型和籼型糙米消化液FRAP值（以Trolox当量计）最大为10.76、8.44?μmol/g,ORAC值（以Trolox当量计）最大为6.82?μmol/g和6.23?μmol/g。     

Iron content and availability studies in some Sri Lankan rice varieties

Thirty‐eight rice varieties, grown in Low Country Wet Zone, during Yala (2006) and Maha (2006/2007) seasons were screened for stable high iron rice varieties and were statistically analysed. Iron contents ranged 1.89–3.73 mg 100 g^?1 and varied significantly (P < 0.05) with variety and season. Selected fifteen high iron rice varieties, at degree of polishing 8–10% were analysed for iron, zinc and phytate. High iron contents in endosperm were observed in Suduru Samba (0.47 mg 100 g^?1), Basmati 370 (0.37 mg 100 g^?1), Kalu Heenati (0.42 mg 100 g^?1), Rathu Heenati (0.44 mg 100 g^?1) and Sudu Heenati (0.37 mg 100 g^?1). Phytate contents of polished rice varieties ranged from 200–300 mg 100 g^?1. Large reduction in iron content (84.5–93.6%) was observed in polished rice while the reduction in phytate content (18.9–40.8%) was low. Percentage dialyzability of iron in selected endosperm high iron rice varieties ranged from 1.73 to 8.71. Dialysability of iron in cooked polished rice did not show a relation to the phytate content in raw rice.     

不同类型大米吸着等温线差异性研究

对11个大米样品（5个粳米、2个籼米、4个糯米）,采用静态称重法测定了水分吸附和解吸等温线数据,温度分别为10、20、25、30、35℃,相对湿度范围11.3%⁹6%,并分别采用修正Chung-Pfost方程（MCPE）拟合等温线。在10³5℃范围内,拟合的粳米、籼米及糯米每个温度水分吸着等温线依次降低。粳米与糯米之间吸附等温线差异显著大于粳米与籼米之间吸附等温线差异,籼米与糯米之间吸湿性相似,粳米与籼米解吸等温线之间差异不显著,但是粳米与糯米解吸等温线之间在10³0℃范围、低相对湿度下存在差异。Mixolab分析仪适量加水实验显示,粳米米粉的吸水率大于籼米和糯米。粳米、籼米、糯米米粉团的蛋白质网络强度（C2）依次减少,但是米粉团淀粉糊化（C3）、糊化淀粉粒的物理溃败（C4）和淀粉回生（C5）减少次序是籼米、粳米和糯米。与籼米比较,糯米米粉团具有弱的蛋白网络、低的淀粉糊化粘度值、低的糊化淀粉粒物理溃败和淀粉回生值,这些物理化学特性不降低其米粉吸水率。      

Comparative study of total phenolic compounds,flavonoids and antioxidant capacities in pigmented and non-pigmented rice of <Emphasis Type="Italic">indica</Emphasis> rice varieties

The total phenolic compounds and flavonoid contents of grains as well as the antioxidant capacities were determined in 15 rice varieties. A high-performance liquid chromatography method was modified for the determination of the flavonoid subgroups in rice grains. The results showed the total phenolic compounds, flavonoid contents, and antioxidant capacities of pigmented rice were higher than in non-pigmented rice. The amounts of flavanone groups ranging from 0.04 to 0.40 mg Naringenin g^?1, while flavones groups ranging from 0.08 to 0.57 mg Apigenin g^?1, flavonol groups ranging from 0.16 to 1.20 mg Quercetin g^?1 and anthocyanin groups ranging from 44.43 to 69.83 mg Cyanidin chloride g^?1 were found in pigmented rice. The total phenolic compounds and total flavonoid contents of grains were significantly correlated with their antioxidant capacities. The results indicated that pigmented rice appeared as a good source of phenolic and flavonoid compounds and had beneficial nutritive values or antioxidant substances.     

含水量和处理温度对人工加速老化试验中水稻种子储藏特性的影响

为了克服已有的高温高湿的人工老化方法受人工气候箱的控温控湿条件的局限性,以确保试验过程中种子含水量和温度的稳定性,本文研究在人工气候箱环境材料间开放和密闭的条件下水稻种子含水量随处理时间的变化规律;进而研究密闭常湿条件下处理30 d的不同温度、不同含水量籼粳材料种子发芽率变化。结果表明,与初始含水量范围相比,储藏过程中粳稻材料和籼稻材料的含水量范围,30 ℃＋RH 75%、30 ℃＋RH 85%的开放储藏条件下,分别缩小为原来的31%和24%、26%和25%,而30 ℃＋常湿、34 ℃＋常湿的密闭储藏条件下,则仅分别缩小为原来的94%和81%、90%和87%;38 ℃＋常湿＋30 d、42 ℃＋常湿＋30 d的密闭储藏条件下,初始含水量差异的粳稻和籼稻材料,发芽率差异最高和最低分别为85.0%和7.0%、98.5%和11%;进一步计算种子人工加速老化处理30 d的发芽率下降百分率,38 ℃＋常湿、42 ℃＋常湿的密闭储藏条件,初始含水量14.00%的粳稻材料和籼稻材料,其发芽率下降百分率已分别达到63.31%和88.83%。初步分析获得:38 ℃＋常湿＋初始含水量14.00%＋30 d＋密闭储藏、42 ℃＋常湿＋初始含水量14.00%＋30 d＋密闭储藏分别是粳稻和籼稻人工加速老化试验最适宜的处理条件。本研究为获得稳定的、可重复的人工加速老化新方法提供理论参考。     

Comparison of lignans and phenolic acids in different varieties of germinated flaxseed (Linum usitatissimum L.)

The study aimed to evaluate the biosynthesis and accumulation of lignans, phenolic acids and also the antioxidant activities in 15 varieties of flax sprouts. The differential contents of lignans (13.30–8987 μg g⁻¹) and phenolic acids (72.55–597.1 μg g⁻¹) among 15 varieties of flax sprouts were observed. The total antioxidant activities ranged from 147.2 to 332.8 μmol TE g⁻¹ in the flax sprouts. The expression levels of five genes in the lignin synthetic pathway were analysed using RT-qPCR, and the results showed dramatical differences among different flax sprouts. Relatively dispersed analysis was showed by principal component analysis (PCA), and 15 flax sprouts were grouped by hierarchical cluster analysis (HCA) based on their phenolic acids, lignan compounds, length, gene expression and antioxidants after germination, primarily in relation to variety specificity. Present results would be instructive guidance for bio-fortification breeding and functional foods innovation in flaxseeds.     

Qualitative and quantitative analysis of the major phenolic compounds as antioxidants in barley and flaxseed hulls using HPLC/MS/MS

BACKGROUND: Both qualitative and quantitative analyses of the major phenolic compounds in barley and flaxseed hulls were conducted using reverse phase high‐performance liquid chromatography coupled with photodiode array detection and quadrupole time‐of‐flight mass spectrometry. RESULTS: Ferulic acid, p‐coumaric acid, vanillic acid and vanillin were identified and quantified in four barley hull samples. Four ferulate dehydrodimers were also detected. The phenolic compounds of flaxseed hull were distinct from those of barley hull. Three flaxseed hull samples varied significantly (P < 0.05) in their contents of secoisolariciresinol diglucoside (16.38–33.92 g kg^?1), coumaric acid glucoside (35.68–49.22 g kg^?1) and ferulic acid glucoside (5.07–15.23 g kg^?1). The phytochemical profiles of co‐extracts featured the major phenolic compounds from both barley and flaxseed hulls. The total phenolic content and 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging capacity varied significantly (P < 0.05) among different varieties of flaxseed and barley hulls. CONCLUSION: As agricultural by‐products, barley and flaxseed hulls may be utilised as potential sources of functional food ingredients through extraction and concentration of the phytochemicals identified above. Copyright © 2012 Society of Chemical Industry     

Release of phenolic acids from defatted rice bran by subcritical water treatment

BACKGROUND: Oil production from rice bran, an undervalued by‐product of rice milling, produces defatted rice bran (DRB) as a waste material. Although it is considered a less valuable product, DRB still contains useful substances such as phenolic compounds with antioxidant, UV‐B‐protecting and anti‐tumour activities. In this study the phenolic acids in DRB were extracted with subcritical water at temperatures of 125, 150, 175 and 200 °C. RESULTS: Analysis of total phenolics using Folin–Ciocalteu reagent showed about 2–20 g gallic acid equivalent kg^?1 bran in the extracts. High‐performance liquid chromatography analysis showed low contents of phenolic acids (about 0.4–2 g kg^?1 bran). Ferulic, p‐coumaric, gallic and caffeic acids were the major phenolic acids identified in the extracts. Thermal analysis of the phenolic acids was also done. The thermogravimetric curves showed that p‐coumaric, caffeic and ferulic acids started to decompose at about 170 °C, while gallic acid did not start to decompose until about 200 °C. CONCLUSION: Subcritical water can be used to hydrolyse rice bran and release phenolic compounds, but the high temperatures used in the extraction can also cause the decomposition of phenolic acids. Copyright © 2010 Society of Chemical Industry     

Anthocyanin content and antioxidant capacity in bran extracts of some Thai black rice varieties

This study investigated both the anthocyanin content and the antioxidant capacity of a set of genetically related glutinous and nonglutinous Thai black rice varieties. The ethanol/water extracts of the brans of these black rice varieties showed relatively potent antioxidant activities compared with those of tocopherol. These antioxidant activities were determined by thiocyanate, H₂O₂‐scavenging chemiluminescence (XYZ), Cu⁺⁺/bathocuproine colorimetry (PAO) and 1,1‐diphenyl‐2‐picrylhydrazyl radical‐scavenging assay. The structural identification and quantification of the black rice anthocyanins performed by high‐performance liquid chromatography coupled with electrospray ionisation and tandem mass spectrometry found cyanidin‐3‐O‐glucoside and peonidin‐3‐O‐glucoside as the major anthocyanins in the ranges of 16.01–34.40 and 2.43–7.36 μg mL^?1, respectively. The comparative study in terms of quantity of these phytochemicals and antioxidant capacity of the black rice bran extracts suggested the contribution of overall phenolic components rather than that of the particular anthocyanin pigments.     

Determination of selenium concentration in rice and the effect of foliar application of Se‐enriched fertiliser or sodium selenite on the selenium content of rice

Atomic fluorescence spectrophotometry was used to determine the selenium (Se) concentration in 30 rice products of different species from Southern China. The Se level ranged from 0.015 to 0.046 µg g^?1. Considering the average daily individual consumption of rice products in Southern China, the average dietary intake of Se supplied by this source is only 6–18 µg day^?1 for an adult. This low Se intake from rice products is mainly responsible for the low total Se intake of inhabitants in Southern China. Foliar spraying of Se‐enriched fertiliser or sodium selenite with 14–18 g Se ha^?1 in the heading stage of rice growth increased the Se content to 0.178–0.421 µg g^?1 in rice products. The concentration and amount of Se‐enriched fertiliser can be varied to achieve an optimum concentration of Se in rice products. The authors suggest that these Se‐enriched rice products can contribute an increase in Se intake of 50–100 µg day^?1 on average if their Se concentration is controlled in the region of 0.15–0.50 µg g^?1. © 2002 Society of Chemical Industry     

Comparison of antioxidant capacity and phenolic composition of peel and flesh of some apple varieties

BACKGROUND: Apples contain a large concentration of phenolic compounds, dependent on factors such as cultivar, harvest, storage conditions, and processing. This study aims to identify the essential phenolic compounds present in various apple varieties, to measure their total antioxidant capacity (TAC) with the CUPRAC (cupric ion reducing antioxidant capacity) and ABTS (2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonate)) methods, and to correlate their TAC values with HPLC findings. RESULTS: The order of TAC (mmol Trolox g^?1 fresh weight) of apple peels determined with the CUPRAC method was: Granny Smith > Amasya > Sky Spur > Ervin Spur > King Luscious ≥ Arap Kizi ≥ Lutz Golden. The theoretically calculated TAC values of HPLC‐quantified compounds, with the aid of the combined HPLC‐CUPRAC method, accounted for 18.4–33.5% of the experimentally observed CUPRAC capacity of peel extracts and 19.5–56.3% of flesh extracts, depending on apple variety. CONCLUSION: In synthetic samples of apple antioxidants, the CUPRAC‐TAC values of constituents, identified and analyzed by HPLC, proved to be additive, enabling measurement of the cooperative action of antioxidants using the proposed methodology. Apple peel showed higher contents of phenolics and therefore higher TAC than apple flesh, confirming the health benefit of the consumption of apples together with peel. © 2012 Society of Chemical Industry     

Variations in cadmium accumulation among rice cultivars and types and the selection of cultivars for reducing cadmium in the diet

A pot trial was conducted with 52 rice cultivars of different types collected from different origins. The results showed that there were great differences in Cd concentrations in straw, brown rice and grain chaff among the rice cultivars grown in a soil containing a Cd concentration of 100 mg kg^?1; the Cd concentrations in brown rice ranged from 0.22 to 2.86 mg kg^?1. The great genotypic differences in Cd concentrations indicated that it is possible to lower the Cd content of rice through cultivar selection and breeding. Significant differences were found in the Cd concentrations of the rice types of Indica consanguinity and those of Japonica consanguinity, but not between their origins. There were significant correlations between straw and brown rice in Cd concentration and in the total amount of Cd accumulated. The distribution ratios of the Cd accumulated in brown rice to the total Cd accumulation in the above‐ground rice plant varied greatly from 12.9 to 137.8 g kg^?1, and there was significant correlation between the distribution ratios and Cd concentrations in brown rice. These indicated that Cd concentration in rice grain is governed by the transport of Cd from root to shoot and also from shoot to grain. Cd concentrations in brown rice also correlated significantly with some important agronomic traits, as well as with nitrogen concentrations, one of the most important criteria for rice quality. Copyright © 2004 Society of Chemical Industry     

Total mercury in milled rice and brown rice from China and health risk evaluation

Total mercury (THg) levels in 440 pairs of milled rice samples and brown rice samples from 15 major rice grain-producing provinces of China were measured and the associated health risk via rice consumption for different age categories of Chinese population was also assessed. THg contents were measured by a direct mercury analyser and the limit of detection (LOD) was 1.5 μg kg^?1. The THg levels for milled rice samples and brown rice samples varied from non-detected to 17.8 μg kg^?1 and 1.5 to 25.4 μg kg^?1, respectively, with a mean level of 3.4 μg kg^?1 and 4.9 μg kg^?1, respectively. The THg levels in all milled and brown rice samples were generally low, except three brown rice samples having concentrations above the legally set value for cereals (20 μg kg^?1 Hg). THg intakes for different age categories were estimated according to THg content and corresponding rice consumption and the associated health risk was evaluated by the corresponding provisional tolerable weekly intake (PTWI) for THg (5.0 μg kg^?1 bw week^?1), which was established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The 50th percentile of the THg intakes via milled rice and brown rice consumption for different age categories was in the range 0.09–0.19 μg kg^?1 bw week^?1 and 0.14–0.27 μg kg^?1 bw week^?1, respectively, well below the PTWI, suggesting that the associated health risk is relatively low. However, the 99.9th percentile of the THg intakes for 2–4-year-old children amounted up to 20.6% of the PTWI (milled rice) and 29.5% of the PTWI (brown rice), which deserves attention.     

Antioxidant activity,fatty acids and phenolic acids compositions of potato peels

The effects of freeze-dried extracts from the peels of six potato varieties as antioxidants in pure soy oil were investigated using the active oxygen method (AOM) procedure, carotene bleaching and linoleic acid oxidation experiments on thin-layer chromatography (TLC) plates. At 9 h under AOM conditions, 20 g soy oil treated with 0.05 g of these extracts attained lower peroxide values (PV, 22.0-28.0 meq kg^?1) than the control oil sample (PV, 109.0 meq kg^?1) indicating very strong antioxidant activities. Oils treated with the same amount of tertiary butylhydroquinone, butylated hydroxyauisol-butylated hydroxytoluene mixture and rosemary extract attained PV of 10, 19.0 and 16.0 meq kg^?1, respectively. Results of the carotene bleaching and linoleic acid oxidation experiments on TLC plates indicated that the antioxidant activities of these extracts were due to the presence of phenolic acids. Among the phenolic acids separated and identified by both high-performance liquid chromatography and TLC, chlorogenic, proto-catechuic and caffeic acids were predominant and appeared to be mainly responsible for the strong antioxidant activities of the extracts. Peels from the red potatoes contained more polyphenols than those from the brown-skinned varieties, but their oil contents were similar.     

Isoflavone content in soy germ flours prepared from two drying methods

Isoflavone glucosides and aglucons in various soybean varieties (Chiang Mai‐60, S.J.‐5, Chiang Mai‐2, Srisumrong‐1, and Nakhonsawan‐1) harvested from dry vs. rainy seasons were quantified. Isoflavone contents of all soy germs ranged from 16.5 to 30.6 μmol g^?1. Regardless of varieties, isoflavone contents in germ of seeds from dry season were higher (P < 0.05) than those from rainy season. The Chiang Mai‐60 germ, having the highest isoflavone content (30.6 μmol g^?1), was selected for germ flour production. Freeze‐dried germ flour contained higher isoflavone aglucons (17.72 μmol g^?1 daidzein; 6.48 mg g^?1 glycitein; 4.28 μmol g^?1 genistein) than those (15.07; 5.59; 3.41) of drum‐dried germ flour. However, isoflavone glucoside contents in freeze‐dried germ flour (3.27 μmol g^?1 daidzin; 1.86 μmol g^?1 glycitin; 1.41 μmol g^?1 genistin) were lower than those (5.22; 3.15; 1.89) of drum‐dried germ flour. Total isoflavone contents of drum‐dried and freeze‐dried germ flours were comparable (34.32 vs. 35.02 μmol g^?1) but more than that (30.16 μmol g^?1) of unprocessed germ flour.     

Activated Carbon and Ion Exchange Treatments for Removing Phenolics and Phytate from Peanut Protein Products

Commercial defatted peanut flour and laboratory defatted peanut meal contained 1.5 and 1.7% phytate, 1756 and 2033 μg g^?1 total phenolic acids and 50 and 120 μg g^?1 neutral phenolics, respectively. Laboratory peanut protein isolate contained undetectable amounts of neutral phenolics, 810 μg g^?1 total phenolic acids and about 1% phytate. The ion exchange treatment removed ≥85% of the phytate and the ion exchange and activated carbon treatments removed 92 and 82%, respectively, of the total phenolic acids from peanut protein isolate. p-Coumaric acid was the major phenolic acid, accounting for 40–68% of the total phenolic acids in all peanut protein products.     

Quantitative NMR imaging study of the cooking of Japonica and Indica rice

NMR imaging was used to follow changes in the water content and distribution during the cooking of Nipponbare (Japonica), Khao Dawk Mali (Indica) and High Amylose (Indica) rice. Samples were cooked in closed glass vials for various times, quenched to stop cooking and then investigated using two-dimensional multi-echo ¹H imaging experiments at 20 °C. Images calculated from the first-echo revealed changes in the water content of the rice grains. T₂ images calculated using the first 16 echoes were converted into quantitatively reliable contour maps of the water concentration using an empirical T₂ vs. water content calibration determined from a series of water/rice starch mixtures. Considerable differences in the rate of water uptake and diffusion, the average water contents and the proportions of under-, optimally- and over-cooked rice were observed for the three rice types studied.     

Varietal variation and correlation of trace metal levels with ‚catechins’︁ and caffeine in Sri Lanka tea

Trace elements, phosphorus, ?catechins’? and caffeine levels in different varieties of Sri Lanka tea have been determined. The range and mean of zinc, copper, iron, lead and cadmium in 73 tea samples were as follows: zinc 22.5–62.5 and 35.0 μug g^?1, copper 10.0–25.0 and 17.8 μug g^?1, iron 40.0–185.0 and 128.1 μug g^?1, lead 0.188–0.561 and 0.426 μug g^?1, cadmium 0.156–0.380 and 0.239 μug g^?1. Significant differences in zinc, iron, lead and cadmium were observed among tea varieties grown at different elevations in Sri Lanka. These levels were also compared with results obtained with samples from other countries. The phosphorus content in ?black tea’? showed correlations with trace metal levels in the order lead>zinc>iron>copper>cadmium. Positive correlation with levels of ?catechins’? were more significant with zinc and cadmium. Caffeine levels were found to be significantly correlated with lead and zinc in ?black tea’?. Studies of translocation of trace metals from soil have involved analysis of various parts of the tea shoot and supporting soil.     

Influence of industrial sterilisation,freezing and steam cooking on antioxidant properties of green peas and string beans

We found that peptides or amino acids constituted the main fractions of water‐soluble nitrogenous compounds in green peas and string beans (44% and 79%, respectively). Their proportion increased after processing, especially in frozen peas and beans (61% and 95%, respectively). The content of phenolic compounds was decreased more after industrial processing (by 40% in peas and 50–70% in beans) than after cooking (by 20% in peas and 0–35% in beans). Antiradical activity against ABTS^?+ (2,2′‐azino‐bis[3‐ethylbenzothiazoline‐6‐sulphonic acid]) was much higher in aqueous extracts of peas and beans (33 and 45 μmol Trolox g^?1 d.m., respectively) than in aqueous acetone extracts (approximately 17 μmol Trolox g^?1 d.m. in both). In most cases, the activity decreased after processing. Both aqueous and acetone extracts of peas showed equal activity against DPPH^? (2,2′‐diphenyl‐1‐picrylhydrazyl), whereas in the case of beans this activity was four times lower in aqueous than in acetone extracts. Both reductions and increases of these activities were noted after processing.