摘要:

ABSTRACTEffect of Ca++on the heat aggregation of whey protein concentrates (WPC) was compared with that of Na+and Mg++. On the alkaline side of the isoelectric zone, aggregation of WPC was increased by the addition of CaCl2, MgCl2or NaCl, among which CaCl2showed the greatest effect. The denaturation temperature of WPC determined by differential scanning calorimetry significantly decreased in the presence of CaCl2or MgCl2, but increased slightly in the presence of NaCl. In the electrophoretic patterns of heated WPC, the most sensitive protein to Ca++was β‐lactoglobul

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14785.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThree‐level fractional factorial experiments were used to study effects of heating conditions (pH, time, temperature, solids content, calcium addition) on whey protein concentrate. Increasing pH and temperature led to lower solubility at pH 4.6 and 7.0, lower sulfhydryl content, higher hydroxymethylfurfural, generally darker color, lower DNBS‐available lysine and altered pepsin pancreatin digestion profiles. Mercaptoethanol and SDS demonstrated relative importance of disulfide and hydrophobic bonds on solubility loss. Polyacrylamide gel electrophoresis indicated heat stability of proteose peptones; susceptibility was greatest at pH 8.0, 95°C for β‐lactoglobulin and α‐lactalbumin, and pH 4.6, 95°C for bovine serum albumin. HPLC gel filtration showed that heating rendered a high molecular weight fraction undissociable by merc

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14786.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTAn improved model for food thickness has been developed which accounts for the transient viscoelastic behavior of food materials. This model, previously tested for spreadability, satisfactorily predicts subjective thickness as well. Subjective scores obtained through the use of ratio scales correlated well with calculated shear stress on the surface of the tongue. The best slope of thickness vs shear stress on the tongue was 0.74 with a correlation coefficient of 0.93. The final result provides a design equation for the thickness of foods from a Theological standpoint.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14787.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTA new method was established to estimate the foaming properties of proteins from the conductivity of foams using a simple apparatus that consisted of a glass column with the conductivity cell. A close correlation was observed between the initial conductivity of foams and the foam volumes of heat‐denatured ovalbumins or 11 native proteins, suggesting that the initial conductivity of foams can be used as a measure of foaming power. In addition, a close correlation was obtained between the foam stability determined from changes in the conductivity and foam volume with time of heat‐denatured ovalbumins or 11 native proteins, suggesting that foam stability also can be estimated from changes in the conductivity of foams. The advantages of the conductivity measurements are to determine the foaming properties more simply and accurately than the currently used meth

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14788.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTDemethylation of pectin was the major change in cell wall constituents which occurred during controlled fermentation of cucumbers. The average degree of polymerization of the pectin was 402 residues. This did not change until 6 months after brining. Galactose, xylose, glucose, mannose, and arabinose were present in order of decreasing abundance in the mesocarp cell walls. These noncellulosic neutral sugars did not change during cucumber fermentation and storage. Mesocarp firmness increased when pectin was demethylated, but the firmness subsequently decreased. Calcium chloride at 20 and 40 mM prevented firmness loss compared to fresh cucumbers during 11 months of storage.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14789.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTSensory evaluations of 20 aroma related characteristics derived using open discussion profile methods were made on 10 different carrot selections. Factor analysis was applied to the sensory evaluations to determine an orthogonal set of descriptors which were derived from the original set of data. Five factors, defining independent aroma characteristics of raw carrots, were determined to be earthy‐organic aroma, basic raw carrot aroma, fruity‐perfumy aroma, nonearthy aromatics, and piney aroma. A second application of factor analysis was utilized to identify components in the head space profile which might correlate with the five newly determined aroma descripti

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14790.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTOils containing different levels of the most common phenolic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tertiarybutyl hydroquinone (TBHQ) from 0–200 ppm were analyzed by a new gas chromatographic method. The antioxidants in oils were isolated by nitrogen gas purging, collected on Tenax GC coated with polymetaphenoxylene, and then separated and quantitated by gas chromatography. This method requires neither extraction of antioxidants from oil nor derivatization of antioxidants. The correlation coefficients (r) between gas chromatographic peak heights or peak area and their concentrations in oils were 0.99 for BHA, BHT, and TBHQ. This simple gas chromatographic method can determine as little as 10 ppm pf BHA, BHT, or TBHQ in oils in an hou

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14791.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe total trypsin inhibitor was determined in extracts of 11 cultivars of soybeans and 11 strains of winged beans. The proteins in the extracts were precipitated by 16% trichloroacetic acid (w/v), and nonprotein trypsin inhibitor activities were determined in the protein‐free supernatants. The nonprotein trypsin inhibitor activities varied between 10.32 ± 1.39 and 24.41 ± 1.04 units/mg defatted soybean samples and in winged beans ranged between 2.65 ± 0.62 and 6.79 ± 0.27 units/mg defatted samples. The nonprotein trypsin inhibitor composed 27–55% of the total trypsin inhibitor activity in the soybeans, and 5–14% of the total activity in win

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14792.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTA mathematical model was developed for prediction of temperature fluctuations in warehouse stacks of frozen peas subjected to dithermal storage regimes. The model was tested by comparing its predictions with temperatures measured in frozen peas packed into a slab‐shaped container. Satisfactory agreement was found between model and experiment. Other model predictions indicate that large container sizes and rapid fluctuation regimes result in the greatest thermal stability at interior locations in bulk‐stored peas. Thermal properties of frozen peas were also determined as part of the experimental verification. The model can be used to evaluate quality changes in frozen products due to di‐thermal storage and the energy needed to maintain a certain final qu

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14793.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTTwelve samples of raw and cooked potato peels from commercial potato varieties were analyzed for their α‐chaconine and α‐solanine content by high‐performance liquid chromatography (HPLC). Raw peels contained 1.30–56.67 mg/100g peel (wet weight) α‐chaconine and 0.5–50.16 mg/100g peel (wet weight) α‐solanine. Raw flesh from the same potatoes contained 0.02–2.32 mg/100g flesh (wet weight) α‐chaconine and 0.01–2.18 mg/100g flesh (wet weight) of α‐solanine. Peels were cooked by baking, frying and baking‐frying. The two types of fried peels contained more α‐chaconine (2.18–92.82 mg/100g cooked peel) and α‐solanine (1.09–72.09 mg/100g cooked peel). Four commercial potato peel products – wedges, slices, fried peels and baked‐fried peels – contained 3.60–13.71 mg α‐chaconine/100g cooked produc

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb14794.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY