THE STRUCTURE OF THE PERICARP AND TESTA OF BARLEY

Detailed microscopic study of the covering layers of the mature barley grain shows that beneath the husk the pericarp consists of highly compressed cell material bound by a thin outer cuticle. The testa is a double cell layer, also bound by an outer cuticle. An innermost cuticular membrane separates the testa from the remains of the nucellus. This membrane is of nucellar origin and not part of the testa. The outer cuticle of the testa is incomplete in the ventral furrow and in the micropylar area of the grain. The absence of the testa cuticle and the relatively uncompressed nature of the pericarp at the micropyle may facilitate uptake of solutes by the embyro.     

茶多酚的应用及提取方法

茶多酚是一种天然的抗氧化剂,在食品加工、医药、日用化工等领域具有重要的应用.主要介绍了茶多酚的组成、性质及应用并对它主要的提取方法作了简要介绍.     

茶多酚对糖尿病大鼠的抗氧化作用

给糖尿病大鼠饲喂添加茶多酚的饲料,检测其血清及肝匀浆过氧化脂质（LPO）和丙二醛（MDA）含量,测定超氧化物歧化酶（SOD）活力,并观察脂蛋白LPO水平和氧化易感性的变化。结果表明,糖尿病大鼠血清LPO和MDA含量显著降低,肝脏及血清SOD活性明显升高,HDL-LPO水平显著减少,在体外进行氧化修饰时,LDL氧化延滞时间明显延长,提示LDL氧化易感性下降。茶多酚对糖尿病大鼠具有抗氧化作用,因此对糖尿病及其并发症的发生和发展能起有效的防治作用。     

FERMENTATION OF CASHEW (ANACARDIUM OCCIDENTALE L.) "APPLE" INTO WINE

Cashew apple is considered as a waste in cashew nut processing industry. An undistilled alcoholic beverage (wine) was prepared by fermenting cashew apple juice with wine yeast, Saccharomyces cerevisiae var. bayanus. The wine was slightly yellowish, acidic in taste (titratable acidity [1.21 ± 0.0 g tartaric acid/100 mL]), high in tannin (1.9 ± 0.22 mg/100 mL) and low in alcohol (7%) concentration. Although sensory evaluation rated the cashew apple wine as quite acceptable as an alcoholic beverage, significant differences (P < 0.01) exist between the cashew wine and the commercial grape wine particularly in taste, aroma, flavor and aftertaste because of probably high tannin content in the cashew wine.     

RELATION OF RHEOLOGICAL PROPERTIES OF TESTA OF PISUM SATIVUM L. TO HISTOLOGICAL CHANGES*

The study was undertaken to determine histological distortions occurring in the pea testa (skin) as a result of various force applications. Multi-directional compression caused bending of macrosclereids and flattening of osteosclereids. Unidirectional pressure caused similar deformations plus eventual separation between cells; shearing caused bending, buckling and wedging of macrosclereids; bruising resulted in cracks between macrosclereids and buckling. The existence of a pentosan-cellulose complex in the basal and apical ends of the macrosclereids and in the end wall regions of the osteosclereids, as established by R. M. Reeve of the U.S.D. A., and the triangular arrangement of the osteosclereids might explain the ability of the macrosclereids to bend and buckle and of the osteosclereids to spread in the end wall regions. This in turn contributes to the resiliency and toughness of the testa in the face of varied physical forces.     

红枣汁中总酚含量的福林法测定

以没食子酸为标准品采用福林(Folin-Ciocaileu)法测定红枣汁中总酚含量,标准曲线的回归方程为:y=0.113 6 x+0.005 4(R2=0.999 3).对其稳定性、精密度、重复性、加样回收率进行了试验,相对标准偏差(RSD)在0.1%～0.71%范围内.     

INTERPRETATION OF COLOUR TESTS FOR POLYPHENOLS AND MELANOIDINS

Melanoidins, both synthetic and “natural”, show colour reactions which are normally attributed to polyphenols.     

从猕猴桃中提取多酚的研究

研究提取猕猴桃中多酚的最佳工艺条件。考察了有机溶剂种类及其浓度、提取时间、温度、提取次数及料液比等5个单因素对总多酚提取率的影响,并在单因素的基础上进行正交实验得到多酚提取的最佳工艺条件:用30%的丙酮溶液,按1∶9的料液比,在35℃下提取30min。     

苹果多酚对冷却猪肉腐败菌抑菌效果的影响

采用平皿培养法和滤纸片法,以抑菌圈直径、菌落总数(cfu)、挥发性盐基氮(TVB-N)和肉色(红度值a)为指标,探讨苹果多酚对冷却猪肉腐败菌的抑菌效果.苹果多酚单独使用时,以0.5%的浓度为最佳,与Nisin结合使用时,二者表现出明显的协同抑菌效果.再与烟酰胺混合使用,抑菌的同时还具有护色效果.     

ANTIOXIDATIVE ACTIVITY OF GREEN TEA POLYPHENOLS IN EDIBLE OILS

The antioxidant activity of green tea polyphenols in several edible oils and fried noodle was investigated. The green tea polyphenols consisted of 27.1% (−)-epigallocatechin-3-gallate, 19.3% (+)-gallocatechin, 16.7% (−)-gallocatechin-3-gallate, 16.1% (−)-epigallocatechin, 8.1% (−)-epicatechin-3-gallate, 7.5% (−)-epicatechin, and 5.2% (+)-catechin. The antioxidant effect of green tea polyphenols in lard and soybean oil was dose-dependent, but tocopherol was less effective. Compared to BHA and tocopherol, green tea polyphenols showed a stronger antioxidative activity on fish oil. Noodles were fried in lard containing green tea polyphenols at several concentrations. The oxidative stability of the noodle was proportional to the green tea polyphenol concentration in lard.     

INHIBITION OF β-GALACTOSIDASE OF APPLE BY FLAVONOIDS AND OTHER POLYPHENOLS

The inhibition of a purified β-galactosidase from "Spartan" apples by flavonoids and related compounds has been studied with a fluorimetric assay using the substrate 4-methylumbelliferyl β-D-galactoside. Certain flavonoids, flavonoid glycosides, phenolic acids, and polyphenols (quercetin, fustin, rutin, p-coumaric acid, and catechol) gave classical noncompetitive inhibition at moderate substrate concentrations. Others (kaempferol, chlorogenic acid) gave nonlinear Dixon plots. The best inhibitors were flavones. In general, the degree of inhibition increased with the degree of hydroxylation and glycosylation of the phenol. Correlation of the structure of these substances with the observed inhibition suggests that the trans-3-(4-hydroxyphenyl)-propenoyl group, common to 4'-hydroxyflavones and p-hydroxyphenolic acids, is important for effective inhibition.     

EFFECT OF VARIOUS POLYPHENOLS ON THE RATE OF HAZE FORMATION IN BEER

The effect of the addition of a range of monomeric, dimeric and polymeric polyphenols to beer on the rate of haze formation has been examined. Monomeric polyphenols had no significant effect on haze formation. The addition to beer of dimeric or polymeric polyphenols caused a large increase in the rate of haze formation.     

大孔吸附树脂分离纯化葡萄多酚的研究

通过吸附、解吸试验，筛选适合分离纯化葡萄多酚的大孔吸附树脂并确立纯化工艺参数。结果表明，AB-8型大孔吸附树脂对葡萄多酚分离效果良好，较佳动态吸附条件为上溶液多酚浓度3．0g／L，pH4．5，上样速率为3BV／h，较佳洗脱条件为乙醇浓度80％，洗脱速率3BV／h，在此条件下，葡萄多酚纯化样品多酚含量为81．1％     

ANTIOXIDANT PROPERTIES OF POLYPHENOLS EXTRACTED FROM GREEN AND BLACK TEAS

The catechins, including epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin gallate (EGCG), and the theaflavins, including theaflavin (TF), theaflavin monogallate (TF-1), and theaflavin digallate (TF-2), were extracted from green tea and black tea, respectively. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging ability, superoxide-scavenging efficiency, and lipid oxidation-inhibition ability of the pure compounds listed above as well as epicatechin (EC), carnosol, carnosic acid, and butylated hydroxytoluene (BHT) were investigated.
The DPPH radical-scavenging ability of the catechins was EGCG > ECG > EGC > EC and of the theaflavins was TF-2 > TF-1 > TF. EGCG, ECG, EGC, TF-2, TF-1, and TF showed higher DPPH radical- and superoxide-scavenging abilities than carnosol, carnosic acid, and BHT. EGCG, ECG, EGC, carnosol, and carnosic acid showed higher lipid oxidation-inhibition activity, as measured by the Rancimat method, than BHT and theaflavins.