摘要:

The rate of degradation of L-ascorbic acid in solution has been investigated under varying conditions, such as temperature, level of dissolved oxygen, pH, amino acids, sugars and processing conditions. Changes in pH between pH 1.5 and 7.0 accelerate L-ascorbic acid degradation. The most important factor that determines its stability is storage temperature, on which the rate of degradation of L-ascorbic acid is directly dependent. Similarly, the deleterious effect of variables such as oxygen and pH are influenced by temperature. Therefore, low temperature storage is imperative in order to regard L-ascorbic acid delay. A definite role of amino acids in L-ascorbic acid degradation has not been identified.

ISSN:0963-7486    

DOI:10.3109/09637489509012538

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

The reproducibility of a 104 item semiquantitative food frequency questionnaire to estimate the intake of energy, fat, fatty acids and cholesterol was assessed in a group of 93 men and women in the Netherlands. The questionnaire was administered by trained interviewers. Subjects were asked to recall the consumption of 104 items during the past month. A second interview was conducted 8 weeks later. The mean difference in nutrient intake between the two assessments was very small, with a maximum of 5% for cholesterol intake, but the variance of individual differences was considerable. Pearson correlation coefficients between two assessments 8 weeks apart ranged from 0.71 for polyunsaturated fatty acids intake (when expressed as percentage of energy intake) up to 0.91 for energy intake. The reproducibility was found to be similar in males and females. Reproducibility was assessed for separate food items as well as for 20 food groups. Items consumed were often highly reproducible and rarely had a poor reproducibility. This food frequency questionnaire is considered to be a suitable tool to estimate and monitor the intake of fat, fatty acids and cholesterol in the Netherlands.

ISSN:0963-7486    

DOI:10.3109/09637489509012539

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Processing of cassava roots by the Alur tribe in Uganda includes a stage of solid substrate fermentation in heaps. Changes in cyanogen levels during the process, microflora involved, and protein levels, amino acid patterns and mycotoxin contamination of the final products were studied. Processing was monitored at six rural households and repeated at laboratory site, comparing it to sun-drying. Flour samples from rural households were analysed for residual cyanogens, mutagenicity, cytotoxicity and aflatoxins. Mean (±SD) total cyanogen levels in flours collected at rural households were 20.3 (±16.8) mg CN equivalents kg−1dry weight in 1990 (n= 23) and 65.7 (±56.7) in 1992 (n= 21). Mean (±SD) levels of cyanohydrins plus HCN were 9.1 (±8.7) in the 1992 flours. Total cyanogen levels in the village monitored batches were reduced considerably by heap-fermentation from 436.3 (±140.7) to 20.4 (±14.0) mg CN equivalents kg−1dry weight cassava. Residual cyanogen levels were positively correlated with particle size of the resulting crumbs. Heap-fermentation was significantly more effective in reducing cyanogen levels than sun-drying alone, but did not always result in innocuous levels of cyanogens. Dominant mycelial growth was from the fungiNeurospora sitophila, Geotrichum candidum and Rhizopus oryzae. No mutagenicity, cytotoxicity nor aflatoxins could be detected in the flours. Protein quantity and quality were not significantly reduced. Cassava gel viscosity pattern was modified to the consumers' preference by this method. As the removal of cyanogens was more efficient and we found no new obvious health risk, heap-fermentation can be regarded as an improvement compared to sun-drying alone in areas where cassava varieties with higher cyanogen levels prevail, but we recommend optimisation of the process for ensuring still safer products.

ISSN:0963-7486    

DOI:10.3109/09637489509012540

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

The dietary patterns of 60 elderly from Spain (37 women and 23 men) were examined by analysis of the food, energy and nutrient intake during 5 days. The caloric profile was somewhat unbalanced, since the percentage of total energy intake from proteins and lipids was above the recommended limit whereas the proportion of energy derived from carbohydrates was slightly deficient. The degree of underreporting derived by subtracting predicted total daily energy expenditure from self-reported energy intake obtained from a diet control during 5 days is 120kcal/day in men and 334kcal/day in women. More than 50% of the population showed intakes of pyridoxine, folates, vitamin A (only in men), vitamin D, vitamin E, zinc, magnesium and iron (only in women) lower than those recommended. Although it is likely that the real intakes of these micronutrients are higher than the levels measured considering the underreporting, the obtained results show the existence of a risk of deficiency of several nutrients. An increase in the energy intake of the group with a parallel increase in physical activity with a view to avoiding weight gain may be of use in improving the nutritional status of the group. This measure, together with increased consumption of vegetables and milk products especially, may lead to a striking reduction in illness, a finding that is of considerable clinical and public health importance.

ISSN:0963-7486    

DOI:10.3109/09637489509012541

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Peanut kernels subjected to pretreatment including rehydration, blanching and dehydration, and untreated kernels were roasted at 160°C for times ranging from 0 to 90 min. For both peanuts, the iron content in oil and specific lipoxygenase activity in defatted peanut flour decreased, free fatty acid content increased and copper content changed insignificantly with roasting time. Changes of iron content, lipoxygenase activity and free fatty acid content were more significant in untreated peanuts than in pretreated peanuts. At each roasting time, iron, copper and free fatty acid contents in the oils and lipoxygenase activities in the defatted flours prepared from untreated peanuts were higher than in the oils and flours prepared from pretreated peanuts.

ISSN:0963-7486    

DOI:10.3109/09637489509012542

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Food samples and ready-made meals from the traditional Italian-type diet were analysed for selenium content. The average Se content varied in food samples from 7μg/kg w/w (fresh fruit) to 226μg/kg w/w (fish). The highest average contents were obtained in the animal products and in legumes. Among ready-made foods the animal derived dishes were the richest in Se, representing 78% of the estimated total daily dietary intake of Se. The average daily dietary intake of selenium for Italian people is estimated to be 50.9±29.8μg Se/day when results obtained on complete meals are used, while it is 45.0±30.8μg Se/day when results on foods and statistical data on consumption are used.

ISSN:0963-7486    

DOI:10.3109/09637489509012543

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Five legumes including chick pea (Cicer arietinumLinn), pigeon pea (Cajanus cajanLinn. Huth.), black bean (Phaseolus vulgarisLinn), mung bean (Phaseolus areusRoxb) and white bean (Phaseolus vulgarisLinn) were cooked and tested for blood glucose response among healthy human volunteers. The blood glucose response to all legumes was significantly lower compared to bread. The glycaemic response to chick pea was significantly lower (P≤0.01) than that to black bean, pigeon pea and mung bean. The glycaemic index of chick pea (13.87±3.0) was significantly lower than those of black bean (27.91±4.0), pigeon pea (30.99±4.1) and mung bean (44.38±5.8) (P≤0.01) but was not different from that of white bean (19.48±4.9). The differences in the glycaemic responses among the legumes could be due to the differences in amount and kind of dietary fibre, amylose content and the presence of antinutrients. Legumes could therefore be added to the list of foods for diabetics and hyperlipidaemics and continuous consumption in larger amounts should be recommended to the general Filipino population.

ISSN:0963-7486    

DOI:10.3109/09637489509012544

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Currently, in nutrition there are major anxieties over the bearing of high intakes of energy and certain nutrients (e.g. fat, sugar) on health/ill-health. Two questions concern sugar: does a high intake (1) cause a deleterious imbalance or dilution of macro- and micro-nutrients? and (2) does it promote degenerative diseases, in particular dental caries? As to the first question, evidence from a variety of contexts indicates that nutrient intakes are not reduced; rather they are increased. Additionally, one accompaniment of a high sugar intake is a reduced intake of fat, one of the primary aims of nutritional guidelines. However, these do not license excessive sugar consumption. As to sugar and degenerative diseases, evidence is lacking that sugar intake is significantly influential other than for dental caries. An examination of evidence indicates sugar consumption to be a weak factor in caries development; its intake explains little of the variance in caries occurrence. Clearly, additional factors are influential - genetic, exposure to fluoride, and dietary components other than sugar. Early detection of the relatively small proportion of caries-prone individuals, by appropriate markers, must be sought.

ISSN:0963-7486    

DOI:10.3109/09637489509012545

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

The recommendation to reduce total and saturated fat is incorporated into the dietary guidelines for the general population in many western countries. In addition, dietary modification to reduce substantially the intake of saturated fats is a cornerstone of treatment in the hyperlipidaemias. Concern has recently been expressed regarding possible deleterious effects of trans isomers of unsaturated fatty acids on the lipoprotein profiles of both normo and hypercholesterolaemic persons. This review seeks to examine recent research in this area with a view to considering possible changes in the present dietary recommendations.

ISSN:0963-7486    

DOI:10.3109/09637489509012546

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Protein concentrates were prepared from unstabilised, acid stabilised, heat stabilised and parboiled rice bran, either freeze dried or roller dried. They were assessed for their nutritional quality by bothin vivoandin vitroassays. The essential amino acid profile of protein concentrates was comparable to rice proteins or rice bran proteins as such. Limiting amino acids of concentrates were threonine and isoleucine. Essential amino acid indices for different samples ranged from 72.4 to 77.6. Lysine content was high (4.32–5.55 g/16gN) of which 52–57% was available. Freeze dried protein concentrate from untreated and acid stabilised rice bran exhibited very highin vitrodigestibility (84.1 and 86%, respectively) whereas protein concentrates from heat stabilised and parboiled rice bran had lower digestibility of 57.3 and 61.2%, respectively. Roller dried samples from untreated and acid stabilised rice bran showed high digestibility with pepsin and pancreatin but low value with pepsin, indicating effect of heat on pepsin digestibility. The results of animal assays can be summarised as follows. The PER values of diets based on protein concentrates from untreated and acid stabilised rice bran at 10% protein level were 2.16 and 2.34 and at 15% protein level were 2.20 and 2.11, respectively. Net protein ratio and nitrogen utilisation from both protein concentrates were also high and not significantly different from the standard protein.

ISSN:0963-7486    

DOI:10.3109/09637489509012547

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor