泰国茉莉香米的检测方法

为了保证泰国茉莉香米品种真实性和纯度,需要建立相应的检测方法并制定方法标准。对新颁布的泰国茉莉香米品种鉴定和纯度检测行业标准所涉及的技术背景和技术要素进行阐述,以促进该方法在相关实验室的应用,为泰国茉莉香米的进口和市场管理提供技术保障。     

Physicochemical properties of KDML 105 rice cultivar from different cultivated locations in Thailand

BACKGROUND: The eating quality of KDML 105 rice cultivar, or Jasmine rice, differs greatly based on its cultivated location. Classifying KDML 105 rice according to its cultivated location could help in understanding the different characteristics of rice which affect its eating quality. RESULTS: The pasting and calorimetric properties of KDML 105 rice from eight locations where Jasmine rice is cultivated were determined using a Rapid Visco Analyzer (RVA) and Differential scanning calorimeter (DSC). Principal component analysis (PCA) was applied in order to classify the cultivated locations of KDML 105 according to their pasting and calorimetric properties. PCA yielded four factors which accounted for 92.7% of the total explained variance. KDML 105 rice cultivated in different locations was subdivided into five areas: (1) the upper central region; (2) the upper northeast region; (3) the lower northeast region; (4) the lower central/northeast region; and (5) the lower northern region and the upper north‐east region. These groups agreed well with the classification of favourable planting areas for Jasmine rice in Thailand. The less favourable cultivated areas correlated either with breakdown and setback or thermal properties. The most favourable locations for quality Jasmine rice in Thailand were correlated with peak viscosity, trough and final viscosity. CONCLUSION: The location of KDML 105 rice cultivation had an impact on cooked rice quality. Pasting and thermal properties of gelatinisation and retrogradation parameters could be used to explain the quality of KDML 105 rice cultivated in different locations. Copyright © 2009 Society of Chemical Industry     

Textural and morphological changes of Jasmine rice under various elevated cooking conditions

The effects of cooking at elevated temperatures (80, 100, 120 and 140 °C) and pressure levels (0, 0.1, 0.3 and 0.5 MPa) on the textural and morphological properties of cooked Jasmine rice were investigated. The developed high pressure cooker was utilized to process Jasmine rice in excess water under isothermal conditions. Rice cooking at higher temperature produced softer and stickier grain texture as well as more off-white colour. Using scanning electron microscopy technique, the microstructure revealed that the soft texture at high cooking temperature corresponded well to the increase of pore size and thickness of the sponge-like texture of inner layer endosperm. As the temperature increased, the outer layer of cooked rice became less porous. Boiling significantly altered the external appearance (namely colour and exterior integrity) and texture of cooked rice while cooking pressure had a little or no effect.     

A new SCAR marker potentially useful to distinguish Italian cattle breeds

In recent years, the safeguarding of Italian native cattle breeds has increased the recovery of these breeds and the promotion of their products by enhancing the application of useful methods to trace the origin of meat products. The random amplified polymorphic DNA sequence (RAPD–PCR) followed by characterised amplified region (SCAR) marker approach could be considered an advantageous method to ensure food quality and origin, and represents a further opportunity to recover Italian autochthonous cattle breeds. Here, we report the results of RAPD–PCR using 42 primers and the development of two informative SCAR markers. Ten different clones for each cultivar-specific RAPD fragment were sequenced and database searches of sequence similarity were performed. The method enabled the detection of low amounts of DNA and, because of the relatively short dimension of the amplicon, it was suitable for the analysis of potentially degraded DNA obtained from processed commercial food that contained meat as an ingredient.     

共显性RAPD标记的检测及应用

将４２个ＲＡＰＤ标记应用于杂交稻组合的Ｆ２群体的１０８个单株进行检测,结果表明：在２个座位分别有２对标记呈共显性分离。这种共显性的ＲＡＰＤ标记可以快速、准确地确定Ｆ２代植株的基因型。     

Non-linear viscoelastic behavior of cooked white,brown, and germinated brown Thai jasmine rice by large deformation relaxation test

Stress relaxation tests at high strain were conducted on scoops of cooked white, brown, and germinated brown Thai jasmine rice using a King Mongkut’s Institute of Technology Ladkrabang test rig. The diameter of the scoop was 35 mm and the height was 10 mm. Non-linear modeling, consisting of four relaxation models, was applied to the data obtained for each type of rice. The modeling methods included Peleg and Normand’s; Yadav, Roopa, and Bhattacharya’s; Jaya and Durance’s; and Myhan, Markowski, and Daszkiewicz’s. The cooked white rice showed greater tenderness compared to the others. The toughness of the three types of cooked rice was not found to be different. The Myhan et al. model was the most accurate in describing the non-linear viscoelastic behavior of all types of cooked rice. The cooked brown rice showed the highest initial decay rate, but the lowest relaxation, lowest elasticity, and greatest viscosity. In contrast, the cooked white rice had opposite characteristics.     

Optimization of operating process parameters for instant brown rice production with microwave-followed by convective hot air drying

Nowadays, instant or quick cooking brown rice is a food product that has marketing potential due to the life style of new generation. This research mainly aimed to characterize, model and optimize the key processing conditions including water-rice ratio (WRR), microwave power level (MWL) and hot air temperature (HAT) for producing instant brown rice by applying Box-Behnken technique. The process responses comprised with color, rehydration ratio and textural qualities of products. The microscopic images of products were also determined. The result indicated that MWL caused the most intense effect on the rehydration ratio and textural qualities. Furthermore, the MWL and HAT influenced on the lightness while the WRR affected on the hardness of rehydrated samples. All three processing parameters significantly affected on the color intensity and stickiness of rehydrated rice. The optimal processing conditions for WRR, MWL and HAT were 1.44, 499.8 W and 89.99 °C respectively with 88% overall desirability.     

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.     

Angiotensin-I-converting enzyme (ACE)-inhibitory peptides from Thai jasmine rice bran protein hydrolysates

Rice bran protein hydrolysate (<50 kDa RBPH) from Thai jasmine variety demonstrating a high Angiotensin I converting enzyme (ACE) inhibitory activity was purified and characterised. ACE inhibitory peptides were obtained from a two-step purification process: gel filtration and preparative reverse-phase high-performance chromatography (RP-HPLC) and then identified by mass spectrometer hybrid quadrupole-time-of-flight. A novel peptide GSGYF in the RBPH was firstly identified and found to have a partial sequence homology of Oryza sativa Japonica Group. This sequence was further synthesised to exhibit as good an inhibition potency with IC₅₀ value of 2.11 µg mL⁻¹ as Captopril (1.15 µg mL⁻¹). The cytotoxicity test revealed that this RBPH is non-toxic against Vero cells. In addition, the <50 kDa RBPH was resistant to in vitro digestion by pepsin and trypsin. These findings suggest that the RBPH containing ACE inhibitory peptides is likely to be safer and healthier than synthetic drugs and can be an effective food supplement for lowering blood pressure.     

烤烟品种的RAPD分析

利用RAPD标记研究了29个烤烟品种的分子指纹和遗传关系。100个随机引物经10个品种筛选,选出18个随机引物对29个品种基因组DNA进行扩增,得到了29个烤烟品种的分子指纹图谱,参照这些图谱,可对不同烤烟品种进行真实性鉴定。以扩增到的79条多态性DNA片段为基础计算29个品种间遗传相似系数,利用UPGMA法作聚类图,可将参试品种分为3个类群。云南省主栽品种K326与近年选育的品种V2、云烟85、云烟317等被归为一类,遗传基础过于狭窄,建议选用一些遗传关系较远的品种进行亲本选配、品种布局;北方烟区主栽品种NC89、地方品种净叶黄及G140等则归为另一类。      

糯米的不同干燥方式对米酒酿造的影响

该实验探究了烘干、阴干两种不同的干燥方法对糯米的基本理化特性、糊化特性和发酵特性的影响。结果表明,与阴干糯米相比,烘干糯米含水量低1.1%、出饭率高5.9%、粗淀粉含量高1.55%、直链淀粉含量高0.14%。两种糯米淀粉糊化曲线显示,烘干糯米体系整体黏度低于阴干糯米,具有较高的衰减值和回生值,糊化温度略微下降。对比两种糯米31℃发酵48 h后酿造的米酒,烘干糯米米酒比阴干糯米米酒总糖含量高59.3%、总酸含量高16.5%,酒精度低2.1%vol。结果表明烘干糯米对比与阴干糯米具有更优良的发酵性能。     

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.     

米糠谷维素提取纯化方法研究进展

谷维素是米糠和米糠油加工过程中极有价值副产品,具有多种生理功能。该文从谷维素组成、生理功能、米糠油皂脚组成及谷维素提取和纯化方法等方面进行综述,重点阐述谷维素提取和纯化方法研究进展。     

Innovative production of multistrain synbiotic product using Thai-pigmented rice and rice bran oil

This study found that the isolated probiotics Lactobacillus paracasei KUKPS6201, L. acidophilus KUKPS6107, L. reuteri KUKPS6103, L. rhamnosus KUKPS6007, L. salivarius KUKPS6202, Bacillus coagulans KPSTF02 and Saccharomyces boulardii KUKPS6005 had high potential for probiotic properties. All strains had antibacterial activity and high antioxidant activity of 1.654 ± 0.017 mg Trolox mL⁻¹ probiotic extract. The selected strains could survive in a simulated gastrointestinal tract under anaerobic conditions and showed no haemolytic activity. Furthermore, the probiotic strains were strongly auto-aggregated and also showed co-aggregated ability with pathogenic bacteria. The probiotic microorganisms demonstrated high ability to adhere to Thai-pigmented rice grains. The results of analysis of these probiotics showed that Riceberry rice bran oil was an excellent prebiotic. A synbiotic product containing Thai-pigmented rice grains (cultivar Riceberry, Luem Pua and Black Jasmine) and rice bran oil was produced. After 8 weeks of storage, the viability of the probiotics in terms of multistrains was 7.36 ± 0.04 log CFU g^–1 (85.78% survival rate). Microbiological safety testing indicated that the amounts of contaminants were acceptable. This study provided the first scientific report on the feasibility of applying Thai-pigment rice, rice bran oil and mixed-culture probiotics as a novel functional synbiotic product.     

稻谷整粒与粉碎水分测试方法的对比分析

通过连续测试在一定含水量区间内的稻谷籽粒含水量,对比分析国家标准稻谷粉碎测试与国外稻谷整粒测试所得的含水量。结果表明,稻谷经粉碎后测试含水量与整粒测试含水量在整个水分测试区间存在较大差异,整粒测试所得含水量大于粉碎测试所得含水量,并且随着稻谷籽粒含水量的降低2种测试方法间含水量差异性逐渐减小,直至稻谷含水量达到11%左右时2种测试方法间无差异。因此总体来说整粒测试方法所得稻谷含水量测定结果更准确可靠。     

米糠蛋白提取方法研究进展

我国米糠资源丰富,其蛋白质含量较高;该文论述提取米糠蛋白作用机理及方法。     

应用粳米淋饭酒母、玉米淀粉喂浆开发清爽型黄酒的工艺

根据嘉兴传统喂饭黄酒在酿制中的原理，结合酶法低温蒸煮新技术，在传统黄酒酿造工艺的基础上，采用粳米搭窝糖化培养制成淋饭酒母，然后在酵母扩培和发酵过程中将粳米喂饭改为玉米淀粉喂浆，并在后道工序中大胆引入勾兑调味技术和冷冻吸附工艺，产品具有清凉透明、香气淡雅、口味爽适、协调、细腻，具有黄酒典型风味。     

Changes in the volatiles,chemical components,and antioxidant activities of Chinese jasmine tea during the scenting processes

Chinese jasmine tea, a type of flower-scented tea, is produced by repeatedly mixing the base tea with the aromatic flowers of Jasminum sambac. The aim of this study was to analyze the changes in the volatiles, chemical components, and antioxidant activities of Chinese jasmine tea during six rounds of the scenting processes. The results indicated that benzyl alcohol, linalool, benzyl acetate, (Z)-3-hexenyl benzoate, methyl anthranilate, indole, and α-farnesene were seven major volatile compounds of jasmine tea. Moreover, the total amount of the volatile compounds increased gradually with increasing scenting rounds. The absorption of linalool became saturated quickly, while those of the other six major volatile compounds exhibited nearly linear increases throughout all six repeated scenting rounds. Importantly, the value of the jasmine tea flavor index, an evaluating indicator of the aroma quality, gradually increased with the progression of the repeated scenting rounds. The change of each detected taste component was less than 15% during six rounds of the scenting process. The antioxidant activities of the tea samples decreased in the first two rounds and later increased in the succeeding four rounds of the scenting process. However, the antioxidant activity of the finished tea was lower than that of the base tea, being significantly correlated with the change of catechin concentration. The findings provided insight into the changes in the volatiles, chemical components, and antioxidant activity of Chinese jasmine green tea during the repetitious scenting process, which could provide beneficial insight on improving the quality grade of the tea.