摘要:

ABSTRACTTwo cultivars of tomatoes were home canned in a boiling water bath with various levels of citric acid and one level of sugar. After 7 months' storage, tomatoes to which lg of citric acid had been added had the lowest ascorbic acid content. Addition of smaller quantities of citric acid, however, did not significantly affect ascorbic acid retention, compared with that of the nonacidified control. Adding 0.5g of citric acid or lg of citric acid plus 1 tsp of sugar was found to be an acceptable method of decreasing the pH of tomatoes used in this study without seriously impairing the flavor or texture.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15227.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTA rapid, sensitive monitoring technique for the detection of microbial contamination of ascptic tomato paste systems has been developed. Samples are aseptically collected by means of a newly developed sampling technique and placed with media in incubation for variable time intervals and are analyzed for the presence of diacetyl or acetylmethyl‐carbinol by means of colorimetric assay or GLC. The technique can detect microbial spoilage in 4–12 hr compared to 72–96 hr using traditional methods. The technique also makes possible the ability to monitor bulk storage tanks automatically by sampling headspace gases above the product and injecting into

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15228.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe feasibility of acidifying home canned tomatoes was determined. Citric acid, lemon juice, or vinegar were added at three concentrations to tomatoes which were canned by the raw pack method. The pH of low acid products was lowered effectively by acidulation with lg citric acid monohydrate or 1 tbsp lemon juice per pint. Vinegar was less effective than the other acidulants and also contributed an off‐flavor at all levels. Acidulants equilibrated more rapidly when added to filled jars rather than to empty jars before filling. Alternative acidulation recommendations were compared by use of data derived from canning studies and from measurements of the response of high pH raw tomatoes to acidulatio

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15229.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTOf 387 jars of tomatoes or tomato juice canned at home in Georgia, seven showed microbial growth indicative of underprocessing or seal failure. Of the remaining 380 jars, the pH of the contents of one jar was 4.65; otherwise all the pH values were below 4.6. Extreme‐value analysis was applied to the pH data to estimate the likelihood of the pH of the content of an individual jar exceeding 4.8. The probability was 0.0014. The total acidity, buffering capacity, ascorbic acid content, grams malic acid required to lower the pH to 4.3 and 4.1, and the vacuum of the container were also determine

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15230.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTA continuous counter‐current diffusion apparatus was used for the extraction of betalaines from red beets. The apparatus was used with an incline of 4.0° and 4.5° and was operated at temperatures from 70‐74°C. The efficiency of water and of citric acid solutions (0.050‐0.125%) to extract betalaines was investigated. The solvent to sliced beet ratios were approximately 1.5/1. Best recoveries of about 71% betanine were found in the more acid systems at 4.5° incline angle. The betacyanine/betaxanthine ratio could be varied and was influenced by temperature and pH of the various processing operations used to produce beet juice powders i.e. diffusion‐extraction, concentration and s

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15231.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThis study was designed to objectively describe the chemical and physical attributes of three pinto cultivars grown at Thrall and El Paso, TX, and Twin Falls, ID. The relationships of these attributes were established through analysis of variance and correlation coefficients. Shear values were found to be the more reliable quality attribute. The expected relationship between rehydration and shear was not found. Maximum imbibition did not yield the most tender product. The amount of water imbibed varied by location. Beans from El Paso that suffered a late frost failed to imbibe water until heat treatment was applied. Firmness was found to be related to calcium and magnesium contents. Sensory preference scores rated the Texas‐grown cultivars over the Idaho‐grown cultivars. Whole, reddish‐brown beans of a mild distinguishable flavor were pref

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15232.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTEffects of equipment model and position of food were examined to determine temperature variability and factors influencing temperature of spaghetti heated in convection ovens in a commissary foodservice system. Significant (P<0.01) differences in temperature were found as food was heated in four models and 12 positions. Factors which appeared to have effect on temperature included oven thermostatic setting, oven power rating, location of heating elements, number of meals heated, number of fans, and the presence of an oven floor. Temperature variability existed and was related to model of oven and position of food. This appeared to be influenced by factors of equipment engineering and use which must be improved if ovens of this type are to be effectively utilized.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15233.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTTwo varieties of whole green beans, prepared by steaming, were held on a steam table (>60°C) with portions removed at 10‐min intervals up to 60 min. Dominant wavelengths and Instron measurements for force, shear peak area and work were determined for the seven holding periods. Varieties were inherently different in color (P<0.01). Holding time affected dominant wavelength (P<0.01), Munsell color (P<0.01), force (P<0.05) and work (P<0.05). Texture, color and overall acceptability were evaluated by a trained sensory panel. A consumer panel also evaluated overall acceptability. Orthogonal comparisons of sensory and objective evaluations for dominant wavelengths, force and work were linear. Acceptability scores were highest at 30‐min heated holding time. Statistical analysis indicated that objective quality control standards could be defined by a range of Munsell colors or dominant wavelengths and/or force and work measurements obtained at optimum holding per

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15234.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe thiamine, riboflavin, vitamin B6, vitamin B12, niacin, biotin, fo‐ late, pantothenate and vitamin C levels in several American wines were determined. Five types of white wine and eight types of red wine were examined. The levels of the eight B‐vitamins were higher in the red wines than in the white. Nutritionally significant levels of riboflavin, vitamin B6and niacin were found in the red wines. Folate levels of the wines were lower than reported in earlier studies. Statistical evaluation of the thiamine data indicated the presence of inhibition in these as‐

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15235.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe increased heat resistance of yeasts in orange concentrates as compared with single‐strength juices cannot be accounted for on the basis of sugar contents only. Citric acid is demonstrated to play a role in the heat resistance of spoilage yeasts in concentrated orange juices. Other major chemical constituents of citrus juices, namely, ascorbic acid and pectin, did not exhibit any significant effect. A model system, based on sucrose, glucose, fructose, citric acid and tripotassium citrate, is pro‐posed for the evaluation of the thermal resistance of yeasts in citrus concentra

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1978.tb15236.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY