DIFFUSION PLATE ASSAY FOR MEASUREMENT OF POLYGALACTURONASE ACTIVITIES IN PICKLE BRINES1

ABSTRACT A modified diffusion plate assay was evaluated for its efficacy in measuring polygalacturonase (PG) activities in simulated and commercial cucumber pickle brines. The diffusion plate assay was capable of detecting low PG activities (7 × 10-5 PG units/mL). Clear zone diameters formed in the diffusion plate assay were highly correlated to changes in specific viscosity obtained by the conventional viscometry assay procedure. Slight, dark-stained zones appeared with an ionic strength of 1.6 (NaCl) and increased in diameter with increasing ionic strength. Ionic strengths of commercial pickle brines (0.9–1.8) did not interfere with the diffusion plate assay for detecting PG activity. The diffusion plate assay was observed to be a suitable and convenient alternative to the viscometry procedure for monitoring PG activities in brines used for the bulk storage of pickles.     

PROTECTION OF CUCUMBER PICKLE QUALITY BY CaNa2EDTA1

The effects of calcium disodium ethylenediaminetetraacetic acid (CaNa₂EDTA) on color, texture and lipid oxidation of fermented and nonfermented cucumber pickles stored in light or dark conditions were investigated. Color (L and hue angle values) of pickles exposed to light was protected against bleaching by CaNa₂EDTA. Also, CaNa₂EDTA suppressed production of TBA‐reactive substances and ethylene indicating protection against lipid oxidation. Force (N) required to penetrate exocarp (peel) tissues of fermented pickles was reduced by CaNa₂EDTA. Measurements of residual CaNa₂EDTA indicated that it was stable in fermented and nonfermented pickles. Treatments with at least 100ppm CaNa₂EDTA were necessary to achieve maximum protection against loss of color and oxidation.     

海参体壁组织蛋白酶B酶学性质的研究

提取并研究了海刺参体壁组织蛋白酶B的酶学性质,结果表明,该酶最适反应pH为5.5,最适反应温度为40℃,在20℃～30℃酶活稳定,金属离子Ca2.、Mg2 、K 、Mn2 、Fe2 、Cu2 和Zn2 均能抑制酶活,其中Ca2 、Mg2 作用微弱,而Zn2 可完全抑制酶活;碘乙酸、EDTA对酶具有一定的抑制作用,亮抑酶肽、抗痛素和E-64对酶可完全抑制.DTI和L-半胱氨酸对酶有一定的激活作用.     

QUALITY OF FISH SAUCE PRODUCTS FROM RECYCLED BY‐PRODUCTS FROM FISH GEL AND KAMABOKO PROCESSING

ABSTRACT

In order to make effective reuse of kamaboko processing wastes and to minimize the amount of waste disposal, the production of two kinds of fish sauces was tried on a small industrial scale from the wastes with or without the addition of the meat of deepsea smelt (Glossanodon semifasciatus). They were fermented for 6 months at room temperature using salt and koji mold. As a control, a fish sauce was also produced only from the deepsea smelt meat. The recovery of fish sauce from the initial mashed mixture ranged between 75 and 79%, depending on the ingredients in the three fish sauce products. The total nitrogen content of the waste sauce and the mixed sauce was lower than that of the control. The levels of the original additives to kamaboko products, β‐carotene and sorbic acid, were very low in these fish sauces. The taste‐active components of the waste sauce and mixed sauces were lower than those of the control. Sensory evaluation revealed that the former two waste sauces were less bitter and higher in saltiness than the control. However, no difference was found in umami taste between these products. These findings suggest that the wastes from kamaboko processing factories could be reused as fish sauce for food condiments.

PRACTICAL APPLICATIONS

Recent development in the food industry in Japan has enabled the surimi‐based products to be mass produced and standardized even in the fish gel, kamaboko trade. However, a serious problem has arisen in the development of kamaboko processing through the discharge of the wastes, i.e., nonstandard products or fragments, from kamaboko processing factories. It is clear that the waste from kamaboko processing factories is transformed effectively into fish sauce by using soy sauce koji mold. As a result, the amount of the discharged wastes from kamaboko factories are able to be minimized because the liquefaction ratio of the fish sauce mushes (moromi) from the wastes after fermentation was high and the products have a high umami taste and agreeable soy sauce‐like flavor.     

改性天然沸石与超临界萃取法分离蜂胶中的铅

研究改性天然沸石分离蜂胶中的铅,并与超临界萃取法作比较,两种方法的除铅效果都很明显,铅含量降低53倍～177倍.用3.6 mol/L的盐酸改性的天然沸石除铅效果最佳.改性天然沸石除铅后比超临界萃取后蜂胶中黄酮的提取量提高了1倍.改性天然沸石除铅后蜂胶中钙、铁、锌等含量也有所降低,尤以钙的降低最明显.     

CONSTRUCTION OF FLOCCULENT BREWER'S YEAST BY CHROMOSOMAL INTEGRATION OF THE YEAST FLOCCULATION GENE FLO1

Yeast flocculation gene FLO1, located on chromosome I of Saccharomyces cerevisiae, has been cloned previously¹⁶. However, it has recently been found that the gene was an in-frame deletion derivative of the chromosomal intact FLO1 gene¹⁹. When introduced into non-flocculent industrial strains, including brewer's yeast, the latter gene, FLO1L, containing an open reading frame of 4,611 bp, conferred stronger flocculation than the former gene, FLO1S, containing an open reading frame of 2,586. By chromosomal integration of the ADH1-controlled FLO1L gene, “gene therapy” of the flocculation behaviour of the parent non-flocculent brewer's yeast was successfully achieved.     

大蒜风味腌渍菜粗提液抑菌效果的研究

为研究大蒜风味腌渍菜汁液杀菌效果及影响因素，利用大肠杆菌（E．coli）、金黄色葡萄球菌（s．aureus）、脆壁酵母（Sfragilis）进行了悬液定量杀菌试验。结果表明：大蒜风味腌溃菜汁液对有害细菌繁殖体及腐败真菌具有比较好的杀茵效果。     

RECOVERY OF PALM CAROTENE FROM PALM OIL AND HYDROLYZED PALM OIL BY ADSORPTION COLUMN CHROMATOGRAPHY

Crude palm oil and crude palm olein were hydrolyzed with lipase from Candida rugosa to produce a free fatty acid (FFA) rich oil. The percentages of FFA produced and carotene degradation after the hydrolysis process were determined. The palm oil and hydrolyzed palm oil were subsequently subjected to column chromatography. Diaion HP-20 adsorbent was used for reverse phase column chromatography at 50C. Isopropanol or ethanol, and n-hexane were used as the first and second eluting solvents, respectively. The objective of hydrolyzing the palm oil was to produce more polar FFA-rich oil in order to enhance the nonpolar carotene bind to the nonpolar HP-20 adsorbent in the column chromatography process. Hydrolyzing palm oil with lipase from Candida rugosa gave 30- and 60-fold, respectively, of FFA in the crude palm oil and crude palm olein in 24 h at 50C. Approximately, 15.56 and 17.48% of carotene degraded in crude palm oil and crude palm olein, respectively. For column chromatography, using isopropanol or ethanol as the first eluting solvent, unhydrolyzed oil and hydrolyzed oil showed the carotene recovery infraction two (carotene-rich fraction) of about 36–37 and 90–96%, respectively. Over 90% of carotene recovery was obtained from     

PURIFICATION AND CHARACTERIZATION OF α‐GALACTOSIDASE FROM PEANUTS1

Alpha‐galactosidase was characterized in two peanuts market types, Runner and Spanish. The enzyme was purified 54 fold using ammonium sulfate precipitation, anion exchange chromatography and Size Exclusion High‐performance Liquid Chromatography. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis indicated that the enzyme has a molecular weight of 30, 000 Da, and isoelectric focusing showed a pI of 5.2. The optimum temperature and pH were 50C and 6.0, respectively. The enzyme had a K_m of 0.221 mM when p‐nitrophenyl α‐D‐galactopyranoside (PNPG) was used as a substrate and 80.8 mM when raffmose was a substrate. Raffmose and galactose were found to be competitive inhibitors when PNPG was the substrate: K_i values were 25.4 and 189, respectively. The enzyme was very sensitive to Hg⁺⁺, Ag⁺⁺ and to a lesser extent to Cu⁺⁺. However, ethylcne diamine tetraacetic acid did not have an effect indicating no requirement for cations. The two peanut types tested showed identical enzyme activities.     

大孔吸附树脂分离纯化白英果红色素的研究

比较AB-8、S-8、X-5、NKA-9、D-3520、NKA6种吸附剂对白英果红色素类化合物的吸附及脱附性能。在静态吸附试验研究的基础上,筛选出效果较好的X-5树脂进行动态试验研究。结果表明：X-5树脂在室温下对白英果红色素动态吸附-脱附较优的工艺参数为：上柱液自然pH值（5．12）,上柱速度3BV／h,溶液处理量6BV,次;脱附剂为95％乙醇,脱附剂的流速3BV／h,脱附剂用量6BV／次。此工艺条件能够满意地分离纯化白英果红色素,树脂可重复使用30次以上。     

四种花草茶总黄酮的提取及精制研究

研究了NKA-Ⅱ和AB-8这2种大孔树脂对杭菊、陈皮、甘草、金莲花4种花草茶中总黄酮的吸附和解吸作用,结果表明NKA-Ⅱ对于4种总黄酮的精制作用均优于AB-8树脂,且经过NKA-Ⅱ精制,黄酮纯度有显著提高:杭菊、陈皮、甘草、金莲花总黄酮纯度分别为精制前的1.93倍、1.43倍、3.05倍和1.77倍.     

PREDICTION OF APPLE FRUIT FIRMNESS BY NEAR‐INFRARED MULTISPECTRAL SCATTERING1

The objective of this research was to predict fruit firmness by developing and evaluating a multispectral imaging system for real time acquisition of scattering images from apple fruit. A circular broadband light beam was used to generate light backscattering at the surface of apple fruit and scattering images were acquired, using a common aperture multispectral imaging system, from Red Delicious apple fruit for wavelengths at 680, 880, 905, and 940 nm. Scattering images were reduced to produce one‐dimensional spectral scattering profiles by radial averaging, which were then input into a backpropagation neural network for predicting apple fruit firmness. The neural network performed best when 10 neurons and 20 epochs were used. With three ratios of spectral profiles involving all four wavelengths, the neural network gave firmness predictions with the correlation of 0.76 and the standard error of 6.2 N for the validation samples.