摘要:

ABSTRACTFactors affecting flour stability are the milling process, the degree of refinement, the storage conditions of moisture and temperature but especially moisture, treatments such as bleaching, and additives such as reactive iron compounds included for the purpose of enrichment. Raw cereal products are susceptible to lipase activity and fat acidity increases, especially as moisture climbs above 12%. In many cases, loss in baking quality correlates with the development of fat acidity and thus fat acidity has often been used as a wheat and flour quality criterion. Raw cereal products tend to show resistance to oxidative rancidity, perhaps through natural antioxidants and morphological compartment‐alization of components. When cooked and dried under mild conditions, susceptibility to oxidative rancidity increases sharply. Dry toasting appears to develop new antioxidants and stability increases. Most cereal products respond positively, but to significantly different degrees, to the antioxidants BHA and BHT and thus shelf lives are extended. Wheat protein concentrate obtained from millfeeds is a very unstable product requiring control of enzymes either by low product moisture and storage temperature or by inactivation of the enzymes and use of antioxidants. Stability of soy‐fortified bread flour blends were affected not only by moisture and temperature of storage but also by the type of soy flour and dough conditioner used. With the dough conditioner sodium stearoyl‐2‐lactylate, soy‐fortified flour blend at 13% moisture lost substantial bread loaf volume potential on storage. Although other dough conditioners were able to largely prevent such substantial losses in loaf volume potential under the same conditions, moisture levels below 13% and preferably below 12% are necessary to avoid development of off odors and off flavors and loss of certain nutrients, particularly vitamin A and

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14446.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTStorage stability in peanut‐based foods is dependent not only upon the conditions under which such foods are held in the various marketing channels, but also upon the genetic, cultural, handling, processing and compositional variations in the raw peanuts used for preparation of the products. Most edible peanut products are those having an attractive and unique roasted flavor which requires special considerations for development and stability. The relatively high oil content of peanuts is an important factor also in storage stabilit

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14447.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTBlue mussels (Mytilus edulis) have been frozen or canned. The raw and processed meats (fresh, frozen and canned) were analyzed for proximate composition and mineral content (23 elements) using spectrograph, atomic absorption spectrophotometer, specific ion electrodes or calorimetric procedure. Initial steaming of blue mussels resulted in significant increase in dry weight of meats, but a decrease in carbohydrates and ash content. Further processing (freezing or canning) tended to increase ash but reduced dry weight and carbohydrate content. Only I, K and Na concentration was significantly reduced upon initial steaming. Further processing (freezing and canning) resulted in significant loss in Mg and K while Mn and Na content showed an increase in concentration. Increase in Na content showed an increase in concentration. Increase in Na content is attributed to high concentration of this element in the brine solution used, while Mn appeared to be concentrated by the blue mussel tissue against a negative gradient when in brine. Essential trace elements were not preferentially leached.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14448.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTAn enzymatic reducing system for metmyoglobin was studied in two species of fish, bluefin tuna (Thunnus thynnus) and jack mackerel (Trachurus symmetricus). In both species, the enzyme was primarily located in the midsection of the fish muscle; it had an optimum pH of 7 and an optimum temperature of 25°C. The enzymatic reducing activity of both species was enhanced by anaerobic conditions and partially inhibited by the enzyme catalase, while sodium chloride was not an effective inhibitor. Ascorbic acid as an electron donor and menadione as a mediator were found to be much less efficient than nicotinamide adenine dinucleotide and methylene blue, respectively

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14449.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTThe individual myofibrillar proteins, myosin and actin, were digested with crude papain (1:125 w/w for 0–3 min). The sodium dodecyl sulfate electrophoretic patterns and the rate of proteolytic hydrolysis were observed. Actomyosin, natural actomyosin and both contracted and uncontracted glycerinated myofibrils were also studied. It was found that the gel pattern of the actin proteolytic digestion suggested that two populations of actin exist; that although actin had the highest rate of hydrolysis in the pH stat, the gels suggested only a very limited proteolysis; that actomyosin is less rapidly digested than myosin; and that the proteins of the myofibrils, especially when contracted, are rapidly cleave

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14450.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTThe effect of the interaction of chicken lactate dehydrogenase isoenzyme 5 with carboxymethyl cellulose (CMC) on some kinetic properties was studied. The effect of pH and the concentration of salt, reduced nicotinamide adenine dinucleotide (NADH), and glyceraldehyde‐3‐phosphate dehydrogenase on binding of chicken LDH‐5 to CMC was determined and found to be qualitatively similar to that observed earlier for the interaction of LDH with the particulate fraction of muscle but showed quantitative differences. Modifications of the catalytic properties of LDH on binding to CMC and muscle particles may be due to interactions between the enzyme and the insoluble support or to a change in the microenvironment of the e

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14451.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTMechanically deboned meat from the frames of mature turkeys was stored, at ‐20°C and 4°C. The effect of storage on the recovery of formaldehyde from the meat was determined by trapping the aliphatic aldehyde in an aqueous solution of 3‐methyl‐2‐benzothiazolinone hydrazone hydrochloride: Although formaldehyde has not been recovered from turkey meat immediately postmortem, its rate of accumulation correlated well with length of storage when other factors were held

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14452.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTGround beef with less than 2% added glucose showed typical spoilage characteristics by gram‐negative psychrophiles during refrigerated storage. In samples containing 2–10% glucose, acids produced at the expense of the carbohydrate lowered the meat pH from 5.8 to 5.0–5.2. This low pH persisted in the meat until all glucose was depleted. During this period growth of the predominant nonpigmentedPseudomonasorganisms was hindered, and no spoilage characteristics such as slime and off‐odors were observed. When the glucose disappeared the meat pH started to rise. Incipient spoilage (off‐odors and tackiness) became apparent when a pH value of 6.0 was exceeded. Lactobacilli counts were slightly higher in glucose‐treated meat than in the control, but no bacterial shift was observed. Instead, the added glucose caused a shift in nutrient utilization by the spoilage microflora. Normally these bacteria attack the nitrogenous compounds in meat, resulting in production of alkaline by‐products and elevated meat pH. In the presence of glucose, the same microorganisms utilized the carbohydrate preferential to other compounds in the meat. The oxidatively formed acids lowered the meat pH, affected the growth rate of the spoilage bacteria and hence retarded spoilage. The addition of2%glucose to ground beef prolonged its average shelf life at refrigerated temperatures from 5 days

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14453.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTGrowth ofPseudomonas fragihad a significant (P>0.05) effect on the color of beef stored at 1°± 1°C. Beef color was measured with a Hunter Color/Difference Meter and percentages of myoglobin (Mb), oxymyoglobin (O2Mb), and metmyoglobin (MMb) on meat surfaces were determined using a Beckman DU Spectrophotometer with a reflectance attachment. As surface growth of P.fragiincreased from log 2.2 to 7.2/cm2during 20 days storage at 1°± l°C, the pH increased from 5.5 to 6.6, free fatty acid values (FFA) increased from 0.62 to 2.60 and percent O2Mb decreased from 100% to 0%. Data indicated that proteolytic and lipolytic degradation products ofP. fragimay be important in decreasing the color stability of beef stored at 1

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14454.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACTYersinia enterocoliticacounts of inoculated beef and pork as determined from confirmed isolates picked from trypticase soy agar plates were similar to the counts of confirmed enamel‐black colonies on bismuth sulfite agar plates. With three strains ofY. enterocoliticaincreases in count occurred on raw beef held over a 10‐day period at 0–1°C. When inoculated raw or cooked beef and pork were stored at 7°C (0–10 days) or at 25°C (0–24 hr) large increases inY. enterocoliticacount occurred. At 25°C the increases inY. enterocoliticacounts were somewhat greater on cooked than on raw products. These differences in count may have been caused by (a) differences in the physicochemical characteristics of the meat (raw vs cooked) and/or (b) differences in the level and type of microbial flora that developed on these products. In addition toY. enterocolitica, StaphylococcusandMicrococcusspp. often were dominant on cooked products,PseudomonasandMicrobacteriumspp.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1977.tb14455.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY