Plant Foods for Human Nutrition

Les recherches sur les flavonols du raisin et du vin prennent une importance croissante, notamment à cause des propriétés vitaminiques et physiologiques de ces polyphénols et de l'intérêt que présentent ces colorants jaunes en génétique. Dans le cas du raisin, on constate qu'il n'existait pas jusque-là de méthode adéquate d'isolement quantitatif des flavonols. Or la chromatographie sur couche mince permet une séparation fine des divers polyphénols, et en particulier des flavonols, sans qu'un traitement préalable du vin soit nécessaire. Cette technique donne en outre la possibilité de récupérer facilement ces flavonols en vue de leur dosage. Au cours des recherches entreprises dans cette direction à la Station Centrale de Technologie des Produits Végétaux (I.N.R.A.) de Narbonne, on a d'abord sélectionné la cellulose comme support et deux solvants de développement. Le mode opératoire établi, fondé sur la chromatographie bidimensionnelle conduit simultanément à la séparation entre flavonols et anthocyanes et à la séparation individuelle des divers flavonols, glucosides et aglucones, qu'il est ainsi possible d'identifier et de doser après grattage et élution. Le dosage global est fondé sur la mesure, à 430 mµ, de l'exaltation de la densité optique due à la formation d'un complexe avec l'aluminium. Dans les conditons précisées, l'exaltation est proportionnelle au nombre de molécule-grammes de flavonols par litre et indépendante de la nature des flavonols. La rutine est prise comme étalon. La précision des résultats est de ± 4 mg/l. Le choix de la chromatographie sur couche mince de cellulose permet l'utilisation de cette méthode dans le cas des moûts, des jus et des extraits. L'application de cette méthode montre que les vins rouges peuvent contenir de l'ordre de 100 mg de ces colorants jaunes par litre (vendange éraflée). Les vins blancs sont très pauvres (de l'ordre de 5 mg/l), sauf s'ils proviennent d'une vinification avec macération des pellicules auquel cas ils sont aussi riches en flavonols que les vins rouges.

Cassava contains little zinc, iron, and β-carotene, yet it is the primary staple crop of over 250 million Africans. This study used a 24-hour dietary recall to test the hypothesis that among healthy children aged 2–5 years in Nigeria and Kenya, cassava’s contribution to the childrens’ daily diets is inversely related to intakes of zinc, iron, and vitamin A. Dietary and demographic data and anthropometric measurements were collected from 449 Kenyan and 793 Nigerian children. Among Kenyan children 89% derived at least 25% of their dietary energy from cassava, while among the Nigerian children 31% derived at least 25% of energy from cassava. Spearman’s correlation coefficient between the fraction of dietary energy obtained from cassava and vitamin A intake was r = −0.15, P < 0.0001, zinc intake was r = −0.11, P < 0.0001 and iron intake was r = −0.36, P < 0.0001. In Kenya, 59% of children consumed adequate vitamin A, 22% iron, and 31% zinc. In Nigeria, 17% of children had adequate intake of vitamin A, 57% iron, and 41% zinc. Consumption of cassava is a risk factor for inadequate vitamin A, zinc and/or iron intake.

Fruit processing by-products may be re-utilized as prebiotic ingredients to minimize the environmental impact of solid wastes generated from food industries. This study investigated the effects of enzymatic-induced hydrolysis on two types of guava purée by-products, particularly the prebiotic activity after its inclusion in yogurt-making. Commercial cellulase and xylanase were applied together or separately on refiner (the seed-rich fraction), and decanter (the pulp-rich fraction); labelled as 150 XY (xylanase); 150 CE (cellulase), 150 CX (combined cellulase-xylanase), and CT (control, untreated). The hydrolysis extents followed the order of 150 XY < 150 CE < 150CX. The ethanolic extracts (EEC) of the treated samples were analyzed on selected sugar content and the prebiotic activity score. Rhamnose and xylose were the main sugar constituents in both refiner and decanter. A two to four-fold increments of prebiotic activity score were observed on EEC of combined cellulase and xylanase treated decanter and refiner. Incorporating the combined enzymatically treated whole guava by-products into UHT fresh milk containing a yogurt starter culture significantly increased the log CFU/mL up to 77.6%, enhanced hardness, stickiness, and adhesiveness ranging from 22.2 to 86.4%, and decreased pH values. Combined cellulase-xylanase treatment can convert guava purée by-products into potential prebiotic sources for food applications.

It is mandatory to assess the allergenic potential of genetically modified (GM) crops before their commercialization. Recently, a transgene [Calcineurin B-like (CBL) protein] has been introduced into tobacco plant to make the crop salt resistance. Therefore, it was felt necessary to assess the allergenic potential of the cbl gene product, which was introduced and expressed in Nicotiana tabacum (tobacco) plant and compared the allergenic effects with the wild-type (WT) counterpart. Bioinformatic analysis revealed that there was no significant sequence homology with known allergens. Also, no difference between the protein digestibility profiles of GM and WT tobacco was found. Rapid digestion of CBL protein (Mol Wt 35 kDa) by simulated gastric fluid (SGF) indicated reduced chances of this protein to induce allergenicity. In addition, BALB/c mice sensitized by intraperitoneal administration of WT and GM tobacco protein showed comparable levels of clinical score, specific IgE, IgG1, histamine level, similar effect on different organs as well as IgE binding proteins. These findings indicate that insertion of cbl gene in tobacco did not cause any additional allergic risk to consumer and the GM and native tobacco proteins behave similarly in both in vitro and in vivo situations even after genetic modification.

The effect of high protein milled rices (IR480-5-9 and IR2153-338-3, 10% protein) on the nitrogen retention and growth of preschool Indian children was assessed in two feeding trials in a residential home. The children were offered, ad libitum, a rice-based diet in four meals daily without vitamin and mineral supplement. The children in the experimental group were given the high protein rice; those in the control group were given a local rice (7% protein). The groups had similar percent apparent digestibility and retention of dietary nitrogen. Statistically significant differences in increase in height and weight between the two groups were not consistently observed at the end of 4.5 to 5 months or 1 year. Possible factors contributing to these results are discussed.

Early sowing of winter and spring barley and oats are in general more effective in relation to the attack of frit fly panicle generation than the later sowing, with the exception of late varieties. Meanwhile, we must have in mind that favourable weather conditions in autumn may enable the insects to prolong their activity and to attack the early sowing crops. As well, drought in autumn and low temperature in the spring which occur very often in this area, delay the germination and sprouting so that the heading time of early sown crops coincides with the time of late sown ones.

The phytoalexins produced after the inoculation of green bean pods (Phaseolus vulgaris L.) with the spore suspension of three fungi viz.Fusarium solani, Penicillium patulum andPhytophthora megasperma were studied. Five phytoalexins were isolated and identified as phaseollin, coumestrol, kievitone, phaseollidin and 6-α-hydroxyphaseollin. Their identity was proved according to m.p., TLC, UV and MS by comparison with authentics. Moreover, the preliminary screening of their antifungal activity was carried out.

Sugar maple (Acer saccharum M.) and red maple (Acer rubrum L.) barks were treated with hot water to extract nutrients in order to explore, for the first time, its potential as safe dietary antioxidants. The organic and inorganic nutrients of these extracts, as well as their safety on human PLB-985 cells differentiated into neutrophils-like cells, were determined. Proximate analysis showed that both bark extracts were low in moisture and fat. Sugar maple bark extract (SM-BX) showed crude protein and ash content higher than those found in red maple bark extract (RM-BX). In addition, SM-BX had total sugars higher than those evaluated in RM-BX, while complex sugars (oligo- and/or poly-saccharides) were similarly abundant in both bark extracts. Furthermore, SM-BX demonstrated a wide array of vital minerals (K, Ca, Mg, P, Na, Fe and Cu) in quantity larger than that evaluated in RM-BX, whereas RM-BX have Zn and Mn levels higher than those found in SM-BX. Phytochemical analyses showed that RM-BX exhibited total phenolic and flavonoid contents higher than those measured in SM-BX. Consequently, RM-BX presented an antioxidant activity higher than that of SM-BX: 2.85-fold ABTS radical cation scavenging capacity and 1.9-fold oxygen radical absorbance capacity. Finally, RM-BX and SM-BX were greatly safe since, at concentration up to 100 μg/ml, they did not modify the viability of neutrophils as determined by flow-cytometry assay using Annexin V-FITC/Propidum Iodide as markers. In conclusion, our in vitro studies indicate that both red and sugar maple bark extracts have a real potential as food additives.