ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17948.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSImmobilized multienzymic systems are responsible for the high efficiency of many physiological reaction sequences carried out in living cells. Chemical and physical means for artificially immobilizing enzymes presents the opportunity for duplicating this efficiency for use in processing operations. Such artificially immobilized enzymes also serve as useful model systems for studying the properties of physiological multi‐enzymic sequences. Factors characteristic of the immobilized multi‐enzymic state are described. Comparisons are made between immobilized multi‐ and single‐enzyme systems and between immobilized and soluble multi‐enz

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17949.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSEconomics of immobilization and characteristics of immobilized enzymes and substrates which are important in treatment of foods are discussed. Methods of immobilizing enzymes and activity and stability of enzymes which may be used in food processing and analyses are controlled and limited by the properties of foods. Specific immobilized enzymes which have been used or show promise for use in food processing and analysis are described.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17950.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSThe advantages and disadvantages of three general systems for immobilizing enzymes (adsorption, entrapment and covalent bonding) are discussed with emphasis on practicality for food processing applications. Only covalent bonding results in complete fixation. For economy and simplicity, adsorption has many advantages but composition of feeds may cause excessive enzyme loss. The combination of adsorption on a phenol‐formaldehyde resin with covalent crosslinking with glutaraldehyde is described for immobilizing lactase and advantages are discusse

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17951.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSIntrinsic kinetics of an immobilized enzyme can be different from that of soluble enzyme due to changes of the macromolecule caused by immobilization. Also transport of substrate to enzymic sites on the inert support creates a hindrance to overall reaction. Such diffusional effects on immobilized enzyme reactions were analyzed in terms of effectiveness factor and film factor employing the theories developed earlier in heterogeneous catalysis. The pore diffusion effect in the design of an integral reactor was analytically treated. A brief discussion was given to the diffusional effects in relation to common kinetic studies of immobilized enzymes.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17952.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSA survey was conducted on the total mercury content of approximately 40 foods, including dairy, poultry, meat and fishery products, cereals, fruits and vegetables, bread and sugar, primarily produced in Michigan. Wet acid digestion and atomic absorption photometry were used in the analyses. The mercury content of most products ranged from less than 0.01 to 0.03 ppm. Fish carried generally higher concentrations of mercury, but no sample exceeded the FDA safety guideline of 0.5 ppm.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17953.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSThe relationship between limpness, sizing and par‐fried solids of French fried potatoes and their effect on the number of servings obtained per 100 lb of frozen product in the volumetric type of operations (fast food chain outlets) was investigated. French fried potatoes, shoe‐string style, which had good sizing and limpness yielded more servings than the ones with poor sizing and limpness. The level of solids in the frozen potatoes had no effect on the number of servings obtained, although it did affect the weight of an individual serv

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17954.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSPrecooled, ascorbic acid treatcd, and control fresh sliced celery samples of varying maturities were evaluated for physical and sensory quality attributes after 6 days post‐harvest refrigerated storage and subsequent canning. Sensory evaluations indicated that early harvested celery was of lower quality than optimum or late harvested celery. Shear‐press firmness measurements were similar for celery samples of different maturities. Pre‐storage cooling of sliced celery, either by vacuum or hydrocooling, improved celery quality. Ascorbic acid additions decreased the rate of browning development on cut surfaces, and was effective in extending the refrigerated shelf life of celery when combined with vacuum or hydrocooling. Drained weight and firmness of canned celery from all treatments increased with post‐harvest refrigerated storage time prior to

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17955.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSThe effect of drying carrots, string beans and peppers to various degrees upon subsequent rehydration was investigated. Rehydration capability at 23°C was lost gradually as drying progressed. Blanching previous to drying under our experimental conditions did not improve rehydration of string beans. In carrots, improvement was observed only upon prolonged rehydration times. Some surface active agents when used as 2.0% presoaks before drying were beneficial for rehydration. Respiration of vegetable tissues measured by Scholander respirometry is decreased upon partial drying; TTC color formation ceases at dehydration between 24% and 40% of fresh weight with carrots and peppers. Loss in respiration capability as shown by TTC staining ceases rapidly when an 80°C temperature is used for drying; this is to be expected as enzymes are heat sensitiv

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17956.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

ABSTRACTSA reliable indicator for microbial quality of dehydrated onions was sought and the effect of brine treatment of onions on final microbial counts was investigated. Enterococci were found to be a better index for microbial contamination in dehydrated onions than coliforms: they multiplied at a slower rate on raw onions and were much more resistant to the process and in storage. In dehydration experiments carried out in the laboratory and in industrial lines it was found that dipping or fluming of onions prior to dehydration in 2–4% salt solutions improved their total counts ca 12‐fold and coliform counts about 32‐fold. The fungi counts of dried onions could be reduced by treating whole onions with saturated steam prior to dehydr

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1974.tb17957.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY