Effect of Steaming, Steam-Drying and Frying on the Provitamins A and Ascorbic Acid Contents of Squash （ Cucurbita Spp.）

Vitamin A deficiency still remains a nutritional concern in Cameroon. Squashes pulp is rich in provitamins A and could help to reduce this deficiency. Unfortunately, in Cameroon, squash pulp is more often reserved for the nutrition of sick people and domestic animals. This study aimed at encouraging the consumption of squash pulp to contribute to vitamin A needs. The contents of a-carotene, all-trans-β-carotene and ascorbic acid were determined respectively by HPLC and titration with 2.6 dichlorophenol-indophenol in five landraces of raw, steamed, steam-dried and fried squash pulp from Cameroon. Moisture and total lipid content were also determined. Peeled pulp squash of 5 cm slice was steamed at 90℃ for 30 min or at 85℃ for 30 min, sliced again at 5 mm thickness and dried at 80℃ during 4 h to obtained steamed or steam-dried squashes. To have fried squashes, 40 g of 1 mm thickness slices pulp were fried in boiling refined palm oil （free of carotenoids） bath at 150℃ during 7 and 10 min. The results obtained showed that steam-drying and frying of squashes leaded to water losses （89%-95%）. As a consequence of this, the a-carotene, all-trans-β-carotene and ascorbic acid contents （expressed in g （100 g）-1 fresh portion） of steam-dried and fried squashes were significantly higher （P 〈 0.05） than those of steamed and raw pulp. However, the retention rate of provitamins A and ascorbic acid was more elevated in steamed than in steam-dried and fried squashes. These results suggest that steam-dried and fried squashes could contribute to fight against vitamin A deficiency while increasing availability of squashes.

Provitamin A Crops: Acceptability, Bioavailability, Efficacy and Effectiveness

Vitamin A deficiency (VAD) is the world’s commonest cause of childhood blindness. More than half of these cases occur in developing countries. Animal sourced foods though good sources of vitamin A are too expensive for poor rural people. Crops biofortified with provitamin A offer a convenient and accessible source of vitamin A. The other micro-nutrient programs of fortification and supplementation require more expensive inputs. Biofortification programs have developed crops that are rich in provitamin A. These crops include: maize, golden rice, cassava and orange fleshed sweetpotato (OFSP). With exception of golden rice, the rest of the biofortified crops have received considerable acceptance among the communities. Both animal and human studies have shown that provitamin A from biofortified crops is highly bioavailable and have capacity to improve vitamin A status. After several years of research and promotion, it is time to fully commercialize provitamin A crops by encouraging farmers to start their large scale production and consumption.

Provitamin D Doped Silica and Polymeric Films: New Materials for UV Biosensor

The original technologies of growing silica films, impregnated with 7-dehydrocholesterol (provitamin D3) on quartz substrates and free transparent films on the basis of polyvinyl alcohol and polyvinyl butyral have been developed. Provitamin D photoisomerization in the films under UVB irradiation was investigated by UV absorption spectroscopy. Remarkable changes in the absorption spectrum of 7-DHC were observed in silica and polyvinyl alcohol films as com-pared with ethanol solution, only in polyvinyl butyral film the spectrum was very nearly, while the spectral kinetics of 7-DHC photoisomerization in all the films was different from ethanol. We suggest that several films have potential as UV dosimeters to measure accumulated ‘antirachitic’ UV dose in the same manner as erythemic UV dose is measured by commonly used polysulphone film.

Genetics of carotenoids for provitamin A biofortification in tropical-adapted maize

Yellow maize contains high levels of β-carotene(βC), making it an important crop for combating vitamin A deficiency through biofortification. In this study, nine maize inbred lines were selected at random from 31 provitamin A(PVA) maize inbred lines and crossed in a partial diallel mating design to develop 36 crosses. The crosses were evaluated in the field in two locations(Samaru and Kerawa) and their seed carotenoid content were determined by high-performance liquid chromatography. The modes of gene action, heritability, and correlations between agronomic traits and carotenoid content were estimated. Additive genetic variances(σ~2a) were lower than non-additive genetic variances(σ~2d) for all the carotenoids, plant height(PH), and grain yield(GY), suggesting a preponderance of non-additive gene action. Broad-sense heritability(H^2) was high(H^2> 60%) for zeaxanthin,days to anthesis, and PH, moderate(30% < H^2< 60%) for lutein and GY, and low(H^2< 30%)for alpha carotene, beta cryptoxanthin, βC, and PVA. Genetic advance as a percentage of mean, considered with H^2, also suggests a preponderance of non-additive gene action for PVA carotenoids. Hybrid variety development is thus an appropriate approach to improving grain yield and PVA. GY showed no significant genotypic correlations with carotenoid content, suggesting that these traits can be improved concurrently. Thus, there is ample scope for improvement of PVA and GY in the sample of tropical-adapted maize.

High-Yielding and Carotenoid-Rich Clones Identification among Thirty-One Cassava Clones with Colored Flesh

Cassava is the second most important food crop produced and consumed in Côte d’Ivoire, after yam. White-fleshed varieties, which are low in total carotenoids, are widespread, while coloured-fleshed varieties (yellow to orange), carotenoid-rich, are rare. However, the consumption of carotenoid-rich cassava varieties could help to alleviate health problems related to vitamin A deficiency. This study aims to identify high agronomic performance, carotenoid-rich and versatile cassava varieties among 31 clones introduced from IITA. They were compared to three controls, Bocou2, Yacé and Bonou2, according to agronomic and technological parameters. Results found that out of the 31 clones, six (I082425, I084157, I084563, I085894, I083774 and I070520) were more productive than the control Bocou2 (46.01 ± 14.88 t·ha-1);the clone I083774 had the highest yield (55.88 ± 6.16 t·ha-1). Twenty-one clones had dry matter contents, ranging from 37% to 41%, significantly similar to Yacé control (42.70%). Thirteen clones had highest total carotenoid contents than the control Bocou2. Clones I084157 and I082425 recorded the highest total carotenoid contents with 17.57 ± 1.92 and 18.39 ± 1.19 μg·g-1 respectively. Overall 31 tested clones were fibrous to varying degrees while 27 clones had mild or neutral post-cooking flavours and 17 clones had poor cooking. The clone I084157 is the best compromise of agronomic and technological desired traits.

Photoisomerization of Provitamin D in Hydrogel Matrix

Study of interfacial processes between incorporated biomolecules and hydrogel matrix is of primary importance for the application of synthetic hydrogels as biomaterials, sensors, etc. Their hydrophilic nature, however, hampers fat-soluble biomolecule incorporation. We synthesized N-isopropylacrylamide (NIPAAm)- and Acrylamide (AA)-based hydrogels with hydrophilic-lipophilic balance that under specific conditions permit homogeneous incorporation of provitamins D3(7-dehydrocholesterol) and D2(ergosterol) dissolved in ethanol. Similarity of provitamins D photoisomerization in such hydrogel matrices with the photoreaction in ethanol shows great potential of the novel material for personal dosimetry of biologically active ‘antirachitic’ UV radiation.

Installing the neurospora carotenoid pathway in plants enables cytosolic formation of provitamin A and its sequestration in lipid droplets

Vitamin A deficiency remains a severe global health issue,which creates a need to biofortify crops with provitamin A carotenoids(PACs).Expanding plant cell capacity for synthesis and storing of PACs outside the plastids is a promising biofortification strategy that has been little explored.Here,we engineered PAC formation and sequestration in the cytosol of Nicotiana benthamiana leaves,Arabidopsis seeds,and citrus callus cells,using a fungal(Neurospora crassa)carotenoid pathway that consists of only three enzymes converting C5 isopentenyl building blocks formed from mevalonic acid into PACs,including β-carotene.This strategy led to the accumulation of significant amounts of phytoene and γ-and β-carotene,in addition to fungal,health-promoting carotenes with 13 conjugated double bonds,such as the PAC torulene,in the cytosol.Increasing the isopentenyl diphosphate pool by adding a truncated Arabidopsis hydroxymethylglutaryl-coenzyme A reductase substantially increased cytosolic carotene production.Engineered carotenes accumulate in cytosolic lipid droplets(CLDs),which represent a novel sequestering sink for storing these pigments in plant cytosol.Importantly,β-carotene accumulated in the cytosol of citrus callus cells was more light stable compared to compared with plastidialβ-carotene.Moreover,engineering cytosolic carotene formation increased the number of large-sized CLDs and the levels of β-apocarotenoids,including retinal,the aldehyde corresponding to vitamin A.Collectively,our study opens up the possibility of exploiting the high-flux mevalonic acid pathway for PAC biosynthesis and enhancing carotenoid sink capacity in green and non-green plant tissues,especially in lipid-storing seeds,and thus paves the way for further optimization of carotenoid biofortification in crops.

The Or Gene Enhances Carotenoid Accumulation and Stability During Post-Harvest Storage of Potato Tubers

Provitamin A carotenoids in staple crops are not very stable during storage and their loss compromises nutritional quality. To elucidate the fundamental mechanisms underlying carotenoid accumulation and stability, we investigated transgenic potato tubers that expressed the cauliflower Orange （Or） gene. We found that the Or transgene not only promoted retention of 13-carotene level, but also continuously stimulated its accumulation during 5 months of cold storage. In contrast, no increased levels of carotenoids were observed in the tubers of vector-only controls or a yellow- flesh variety during the same period of storage. The increased carotenoid accumulation was found to be associated with the formation of lipoprotein-carotenoid sequestering structures, as well as with the enhanced abundance of phytoene synthase, a key enzyme in the carotenoid biosynthetic pathway. Furthermore, the provitamin A carotenoids stored were shown to be stable during simulated digestion and accessible for uptake by human intestinal absorptive cells. Proteomic analysis identified three major functional groups of proteins （i.e. heat shock proteins, glutathione-S-transferases, and carbohydrate metabolic proteins） that are potentially important in the Or-regulated carotenoid accumulation. Our results show that regulation of carotenoid sequestration capacity is an important mechanism by which carotenoid stability is regulated. Our findings suggest that induction of a proper sink structure formation in staple crops may provide the crops with a unique ability to promote and/or stabilize provitamin A accumulation during plant growth and post-harvest storage.

Breeding Major Cereal Grains through the Lens o~ ~iutrition Sensitivity

Cereal grains are the common food staples that collectively provide over 50% of dietary calories and proteins for the world＇s population. Although the Green Revolution has greatly increased the yield of commercial cereal crops, they often lack nutrients essential for human health in the edible tissues. In developing nutrition-sensitive agriculture, the nutritional quality of cereal grains has been a major target for improvement using breeding and biotechnology approaches. This review examines recent progress on biofortification of micronutrients （provitamin A and folates） and an essential amino acid （lysine） in three major cereal grains, wheat, rice, and maize, through plant breeding. In addition, how natural variations, induced mutations, and the advanced genome-editing technologies can be applied to improving the nutrient content and stability in these cereal grains are discussed. High-yield cereal crops pyramided with improved （micro）nutrient contents hold great promise to meet the increasing demand of nutritionally limited popula- tions and to contribute to achieving sustainable nutrition security.

Physicochemical,microbiological and sensory properties of low fat yoghurt fortified with carrot powder

Yoghurt is considered as a healthy food and incorporating carrot powder will make it even healthier.Carrot powder is a good source of beta carotene and provitamin A.The objective of this study was to determine the effects of adding carrot powder on the physicochemical,microbiological and sensory properties of low fat plain yoghurt.Plain and carrot yoghurt were prepared in the laboratory scale production using low fat milk.Carrot yoghurt was prepared by blending low fat milk with 1%,2%and 3%carrot powder before fermentation.Physicochemical analysis revealed a decrease in pH value and an increase in titratable acidity,viscosity and total soluble solids with the increase of carrot powder.On the other hand,protein content decreased with the increase of carrot powder.In terms of the lightness(L*)and the redness(a*),3%carrot yoghurt had low values of lightness while it had higher values of redness.Microbial count showed the significant difference between the 3%carrot yoghurt and 1%and 2%carrot yoghurt.There was a significant difference on the sensory scores of colour and aroma of carrot yoghurt and plain yoghurt as the carrot yoghurt got higher scores than plain yoghurt.There was no significant difference(p<0.05)between the acceptability of the plain yoghurt,1%and 2%carrot yoghurt and a significant difference was there between 3%.Thus,fortifying yoghurt with 1%and 2%carrot powder produced acceptable yoghurt with beneficial health effects.