摘要:

SUMMARY—The effect of selected compounds on flavor of various potato products was studied by sensory panels. The minimum detectable amount of each of six compounds in four brands of dehydrated mashed potatoes was determined. The difference thresholds of the six compounds in the reconstituted potato products varied from 0.05–3.1 ppm. Only 2‐methoxy‐3‐ethylpyrcxine (0.1–0.2 ppm) was effective in increasing the flavor level of all four brands of dehydrated potatoes; it also proved to be effective in increasing the potato flavor level of potato salad, dehydrated scalloped potatoes and potato soup. Potato salad stored at 3°C for 1 wk required at least 0.2 ppm of this compound to maintain its initial flavor difference from the co

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06363.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—Storage stability of the color was tested alone and in various citrus products using an extraction process which had been developed for obtaining a highly colored concentrated extract from orange peel. When concentrated color extract was added to single‐strength orange juice in tin‐lined or enamel‐lined cans or clear glass bottles, color stability was good during storage at 35° F; except for some fading in glass‐packed samples, no notable changes in color were observed after 10 wk. However, at 70° F and 85° F color changes occurred, mainly from darkening due to browning. These storage changes were more predominant in glass‐packed juice and enamellined cans. Color in frozen concentrated orange juice remained stable more than 10 wk, showing no notable change in color during storage at −5° F. Stored in the concentrated form the color extract required protection from light and heat. Color was stable for more than 6 months when stored at

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06364.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—A study was carried out to evaluate the nutritive value of opaque‐2 corn grown in Brazil and the nutritional effects of its mixture with hybrid corn and wheat flour. These studies were conducted with rats to determine the growth rate, feed efficiency and protein efficiency ratio. Amino acid analyses of Brazilian opaque‐2 corn confirmed its high lysine content and other differences in amino acid content; nutritive value was shown to be similar to the American variety. There were small variations among samples of opaque‐2 corn grown in different regions and crop years, but all had high nutritive value. The nutritive value of the hybrid corn was little improved by its mixture with the high lysine opaaue‐2 corn. Better results were found when the opaque‐2 was mixed with the

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06365.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—Glandless cottonseed meals were prepared under controlled conditions in a pilot plant by three different processing methods. These meals along with a glandless cottonseed meal produced at a commercial oil mill were used as source meals for protein isolates. Two protein fractions differing in composition and characteristics were isolated from each type meal using a two‐step, two‐solvent isolation procedure developed at the USDA Southern Utilization R&D Div. yields of each isolate precipitated at three different pH levels were determined on the pilot plant meals. Isolate yields from the commercial meal were determined near the respective isoelectric points of the two fractions. Functional properties including whippability, heat gelation, solubility and foaming properties, were measured on all isolates. Variation in measured values due to meal processing method and precipitation pH was statistically assessed in some instances. Meal processing method was found to significantly affect the yield of Isolate I, the minor isolate. pH of precipitation was found to significantly affect the yield of Isolate II, the major isolate. Also, it was shown that the pH‐solubility profiles of both Isolates I and II could be altered by changing the pH at which they were precipitated. The functional properties of isolates from meals processed without heat were superior to those of isolates from heated meals. Data collected indicated the need for a new practice in evaluating the extent of denaturation of cottonseed protein products. The present practice of determining nitrogen solubility at one point was shown to be ina

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06366.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—A procedure was developed for predicting the transient temperature of a solid food exposed to time variable ambient temperatures. Duhamel's theorem was applied to the empirical formulas used for calculating the temperature of a food subjected to a step change in its ambient temperature. The formulas contain two constants: f, the slope index of a heating or cooling curve of a food; and j, the intercept coefficient of the heating or cooling curve. With the procedure developed transient temperature can be estimated without regard to the geometric shape of the food provided the f and j values are known. A table is presented to reduce computations involved in the procedure. Sample calculations are given for a fresh orange, a fresh carrot and a canned food produc

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06367.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—By applying the normal restrictions of thermal inactivation experiments, Ball's general equation for lethality during logarithmic cooling was reduced to a form requiring no exponential integrals. The computation is brief within the limits of two restrictions, and accuracy is ±1% of Ball's general equation. The equation is limited to thermal inactivation experiments where the minor dimension of the sample is less than 15 mm; it cannot be applied to commercial sterilization process

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06368.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—Experiment were conducted to determine the influence and/or effect of the structure of the dried material itself on transport rates. Drying rates were measured in the 0.2–3.0 mm Hg pressure range, the usual operating range of commercial freeze driers. Thermal conductivities of dried beef and heat and mass transfer were calculated from drying rate data and the structure of the freeze‐dried material was studied by optical means. A simplified relationship between thermal conductivity and pore structure was derived. Results show drying rates were related to basic transport properties, thermal conductivity and pore stru

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06369.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—Frozen par‐fried French‐fry cuts allowed to thaw and held several hours before being finish‐fried lost more weight (due to loss of moisture) and absorbed more fat than it not held. The yield of finished product decreased about 7% and fat uptake increased about 25% when par‐fries were held for 3 days at 50°F. Smaller but economically significant changes occurred in only 1‐1/2 hr at this temperature or in 5 hr at 40°F. The rate of the change in par‐fries which causes lower yields and greater fat absorption increases with increasing temperature. The time course of the change at 50°F is similar to that of starch retrogradation in par‐fries but the rote of retrogradation decreases with increasing temperature; therefore, these appear to be unrelated phenomena. There is no combination of time and temperature for frying par‐fries from the thawed state which is equivalent in all respects to a given combination for frying them f

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06370.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—Flow conditions in tubular, cellulose‐acetate reverse osmosis membranes were varied by changing the flow rate and by inserting turbulence promoters (rods with intermittently‐spaced rings cemented to them) in the tubes. In general, increasing the flow velocity increased the permeation rate. Turbulence promoters were most effective in increasing permeation rate under conditions that, in their absence, permitted fouling of the membrane surface by macrosolutes from the feed. When the feed contained macrosolutes, increasing the flow velocity or use of turbulence promoters increased retention of lactose and potassium. Modifying the flow conditions to increase turbulence improves performance of reverse osmosis membranes by increasing both permeation rate and rete

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06371.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SUMMARY—Among the advantages of processing tomatoes in the field, compared with processing solely at a cannery, are increased yield and reduced waste. Mechanically harvested tomatoes were processed at 500 lb/hr through a mobile field unit within 6 hr after harvest during the 1969 season. Processing within 6 hr from harvest prevented a loss of about 9.5% of the ripe tomatoes that occurred when processing was delayed 24 hr. An increase of 4.3% in solids recovery was obtained by acid treatment of the hot macerate, bringing the total increase to 13.8% for field processing. Either the single strength or concentrated material is suitable for bulk transport to a cannery for storage, additional concentration, or immediate formulation into sauces, catsup and other tomato product

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1971.tb06372.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY