Changes in nitrogen content and amino acid composition of navel oranges during ripening

Nitrogen content and composition of amino acids in juice and rind of navel oranges were studied. The compared varieties were ‘Navelina’ ‘Washington Navel’ and ‘Navelate’, early, mid-season and late types, respectively. Total N content in juice increased during the season with values from about 60 to near 100 mg 100 ml^?1 in Navelina and ‘Washington Navel’ and from 60 to about 80 mg 100 ml^?l in ‘Navelate’; amino N increased from 30 to 60 mg 100 ml^?lapproximately in the three varieties. The total N content in rind was quite similar in all cases, with values that decreased with time from 1 to around 0·6 g 100 g^?l dry weight (DW), 50–60% corresponding to the protein N. The main free amino acids in juice and rind at different maturity stages are tabulated. Proline represents at maturity around 50% of the total free amino acids in rind, with values near to 1·5 mmol 100 ml^?l in juice and over 5·0 mmol 100 g^?1 DW in rind. Total protein amino acids in rind decreased during maturation, reaching final values of about 20 mmol 100 g^?1 DW. Differences in composition among the three studied varieties are discussed.     

Effect of the side chain size of 1‐alkyl‐pyrroles on antioxidant activity and ‘Laba’ garlic greening

Previous studies showed that 1‐alkyl‐pyrroles not only occur in fresh food products postulated as a natural antioxidant but also might be involved in garlic greening. In the present study, a series of 1‐alkyl‐pyrroles with different side chain size were synthesised to study the relationship of structure and antioxidative activity and their effects on ‘Laba’ garlic greening. The antioxidative activity of these compounds was evaluated by the method of scavenging ABTS˙ and DPPH˙. Results showed that increasing the size of R groups on the side chain, the antioxidative activity decreased gradually against the two radicals. The 1‐alkyl‐pyrroles generally exhibited stronger scavenging activities against ABTS˙ than DPPH˙. In contrast, their corresponding amino acids except for tyrosine showed almost no antioxidative activities while pyrrole exhibited much weaker activity as compared with the 1‐alkyl‐pyrroles, suggesting that the 1‐alkyl‐pyrroles donate H‐atom from pyrrole moiety rather than side chain to quench the two radicals. On the other hand, all 1‐alkyl‐pyrroles can turn newly harvested garlic green but to a different extent. All these results suggested that these pyrrole derivatives occurring in foodstuff played an important role in either protecting foodstuff from oxidation or acting on pigment precursors during ‘Laba’ garlic greening.     

Modelling the consensus and differences between assessors inspecting the colour quality of apples by ‘tree‐based modelling’

This research investigated the consensus and differences between different quality inspectors assessing the colour quality classification of a two‐coloured apple variety (Malus domestica Borkh cultivar ‘Jonagold’). An image analysis system measured the colour characteristics objectively. These objective measures formed the basic reference to compare the grading behaviour. Different quality inspectors were asked to assess the colour quality of different sets of apples applying the commercial quality standards. Agreement and association measures of the intra‐inspector contingency tables indicated a moderate ability of the inspectors to reconstruct their own quality classification. If the intra‐agreement and intra‐association were lower than a threshold, the repeatability of the inspector's assessments was considered as too poor and his classification results were omitted from the model development that simulated the apple colour classification behaviour. The statistical method ‘tree‐based modelling’ was applied to connect the individual quality assignments with the objective apple colour measurements. These models indicated that the blush colour was more important than the blush area for the quality assessment.The individual grading decision models were compared by correspondence analysis. Four different grading archetypes were detected and simulated. The predictive power of the four archetypal models was much higher than the predictive power of a consensus model including all inspectors. These results underlined the fact that poorly defined commercial standards lead to different quality interpretation. © 2000 Society of Chemical Industry     

Chemical Evaluation of Musa ‘Bhimkol’ as a Baby Food

The edible pulp of Musa ‘Bhimkol’ was analysed for certain organic compounds and mineral nutrients at two stages of development of the fruit to evaluate it as a baby food. Energy value and carbohydrate concentration increased substantially as the fruit ripened so that 16.8% of the energy requirement (recommended daily allowance, RDA) for six-month-old infants would be met by 100 g of the fresh pulp. Although vitamin C content decreased at maturation, 7% of the RDA would be provided by 100 g fresh pulp. The fruit was found to be very rich in macro- and micronutrients, and 100% of the six-month infants RDA for K, Mn, Zn and Se would be satisfied with 100 g of fresh pulp. This amount of pulp would also provide 86%, 57%, 24% and 12% respectively of the Mg, Cu, Fe and P RDA. P and Mg were found to be more highly concentrated in the ripe than in the unripe fruit whereas the reverse was the case for Ca and Se. Aspartic acid, glutamic acid and leucine were the major amino acids in the ripe fruit and respectively constituted 13.1, 12.5 and 7.9%, of the total. The concentration of essential and non-essential amino acids was much higher than that in a commercial banana. Twelve of the 17 amino acids analysed were more concentrated in the mature compared with the green fruit, and 11 of these were an order of magnitude higher than in M paradisiaca L banana. The results of the present study demonstrate that Musa ‘Bhimkol’ is a nutritious baby food.     

Fatty Acid Composition of ‘Cerrado’ Seed Oils

The seeds of 28 species from ‘cerrado’, a typical savanna ecosystem of Brazil, were analysed for total lipid contents and fatty acid distribution. The seeds of 10 species presented contents above 150 g kg⁻¹, the highest yield reaching 335 g kg⁻¹. Distribution of fatty acids based on polyunsaturated compounds seems to be rare in seed oils from ‘cerrado’: only three seed oils were found to be based on linoleic acid and none on linolenic acid. Eight seed oils, four of them Fabales, presented palmitic acid as a dominant constituent. Half of the species presented oleic acid based seed oils. Two species stand out for unusual fatty acid distribution: Qualea grandiflora (Vochysiaceae) with 171 g kg⁻¹ of seed oil presenting 723 g kg⁻¹ of lauric acid and Serjania erecta (Sapindaceae) with 256 g kg⁻¹ of seed oil presenting 623 g kg⁻¹ of eicosenoic acid.     

A yeast gene encoding a putative RNA helicase of the “DEAD”-box family

An unknown open reading frame from Saccharomyces cerevisiae was identified and sequenced. The predicted amino acid sequence shows high homology to the DEAD-box family of proteins. Gene disruption revealed that the gene is not essential for yeast but necessary for normal cell growth.