摘要:

ABSTRACTThe rabbit muscle contractile proteins, myosin, actin and reconstituted actomyosin were mixed in 0.1–1.0 M KCl, 20 mM buffers, pH 5.0–8.0, and were tested quantitatively for thermally induced gelation properties by measuring the rigidity (shear modulus) of the system at 20–70°. Scanning electronmicroscopy (SEM) was also used to study the structure of the gels formed by gelation of myosin in the presence of F‐actin. Under the standard condition, i.e. at 0.6 M KCl, pH 6.0 and 65°, decrease of the myosin/actin mole ratio to about 1.5–2.0 in the reconstituted acto‐myosin system resulted in substantial augmentation of the rigidity of the gel formed. Further decreases in the myosin ratio relative to F‐actin reduced the rigidity value of the gel to close to the level of myosin alone. Gel‐formability of the reconstituted actomyosin was maximal at pH 5.5–6.0 and between 0.5 and 0.8 M KCl and decreased considerably at other pH values and KCl concentrations.The SEM studies revealed progressive changes in three dimensional ordering as actin concentration in the actomyosin varied. These were in concordance with the resu

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00646.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTProteases from autolyzedSaccharomyces carlsbergensiswere partially purified by ammonium sulfate precipitation and hydroxyapatite column chromatography. pH optima at pH3.0and6.8were observed. A7.4‐fold purification was achieved for the protease with neutral pH optimum. The general properties of this enzyme were studied. It displayed optimum activity and stability at37°C and pH6.It was inhibited by Fe+2and Fe+3,N‐ethylmaleimide (NEM), phenylmethanesulfonyl fluoride (PMSF), and sodium chloride (NaCl). It was activated by β‐mercaptoethanol a

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00647.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTEthylene(10ppm) dependent mediation of normal and mutant (rin) tomato fruit ripening was promoted by100%oxygen,3.7pphm ozone, or their combination. All ripening indices studied (respiration, chlorophyll degradation, carotenoid accumulation, softening, and aroma development) were promoted by oxygen and/or ozone. Ozone also acted independent of ethylene in promoting chlorophyll degradation and aroma development in normal fruit, but did not appreciably affect these quality attributes in mutant fruit. Lycopene accumulation in normal and mutant fruit and aroma formation in normal fruit were promoted to a greater extent by ozone than were other ripening indices. Mutant (rin) fruit contained 27% of the lycopene that was present in normal (Rin) fruit after ripening in O2containing10ppm ethylene and3.7pphm ozone, whereas they contained only3%of the lycopene in normal fruit after ripening in air containing10ppm ethylene.

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00648.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTA number of methods for determining dietary fiber have been suggested. Thus, ten modifications of the neutral detergent fiber (NDF) procedure were compared using spinach, bread, and parsnips. Use ofBacillus subtilisalpha amylase resulted in lower (p<.01)NDF values than did porcine pancreatic amylase. Amylase obtained fromB. subtilismay contain other enzymes such as hemicellulase and cellulase in small amounts. These enzymes would be undesirable since they may remove some of the fiber fraction, hence the reported NDF would be lower. Temperature of incubation,21°C or37°C, did not significantly affect fiber values. Samples predigested with amylase had higher (p<.01)fiber values in a high starch food than samples in which amylase incubation occurred after detergent digestion. NDF values may have been higher because starch was less available for enzymatic hydrolysis before the detergent digestion. When amylase was added directly to the detergent solution after refluxing, NDF was not significantly different (p<.05)from that quantified by the official AACC method or most of the other treatments. Implications of these findings are discussed with respect to their significance in practical application

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00649.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTA trypsin inhibitor isolated from black gram(Phaseolus mungoL.) had75amino acid residues with an estimated molecular weight of7892.The kinetic constants Kmand Vmaxas evaluated by the Dixon and Cornish‐Bowden plots were2.7 × 10−5and6 × 10−3M/min, respectively. The dissociation constants of the enzyme‐inhibitor complex (Ki) and the enzyme‐inhibitor‐substrate complex (Ki') were respectively4 × 10−7M and1.9 × 10−6M. Trypsin inhibition by black gram trypsin inhibitor was of a linear‐mixed type. Chemical modification studies suggested the possible involvement of lysine and arginine at the active

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00650.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Book Reviews in this article.Developments in Meat Science ‐ 1.Edited by Ralston Lawrie.Developments in Food Carbohydrate ‐ 2.Edited by C. K. Lee.Dietary Fibers: Chemistry and Nutrition.Edited by G. E. Inglett and S. Ingemar Falkehag.Food and Health: Science and Technology.Edited by G. G. Birch and K. J. Parker.Plant Pigments, Flavors and Textures: The Chemistry and Biochemistry of Selected Compounds.by N. A. M. Es

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00651.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1980.tb00645.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY