Probiotic potentials of cereal-based beverages.

Probiotics offer remarkable potential for the prevention and management of various infective and noninfective disorders. They are reported to play key roles in the suppression of gastrointestinal infections, antimicrobial activity, improvement in lactose metabolism, reduction in serum cholesterol, immune system stimulation, antimutagenic properties, anticarcinogenic properties, anti-diarrheal properties, and improvement in inflammatory bowel disease. Although probiotic foods are classically confined to beverages and cheese, containing live organisms of the lactic acid bacteria family, such health-promoting foods are traditionally dairy-based, comprising milk and its fermented products. However, recent research focuses on the probiotic potentials of fermented cereal-based beverages which are especially consumed in developing countries characterized by low nutritional security and high incidence of gut pathogen infections. Moreover, lactose intolerance and cholesterol content associated with dairy products, coupled with the vegetarian tendencies of diverse populations in the third world, tend to enforce the recent recourse to nondairy beverages. Probiotic microorganisms are mostly of human or animal origin; however, strains recognized as probiotics are also found in nondairy fermented substrates. This review examines the potentials of some traditional cereal-based beverages to serve as probiotic foods, their microbial and functional properties, as well as their process optimization and storage for enhanced utilization.

Analysis of two L-Galactono-1,4-lactone-responsive genes with complementary expression during the development of Arabidopsis thaliana.

Unraveling the role of genes annotated as protein of unknown function is of importance in progression of plant science. l-Galactono-1,4-lactone (l-GalL) is the terminal precursor for ascorbic acid (AsA) biosynthesis in Arabidopsis thaliana, and a previous study showed two DUF (domains of unknown function) 642 family genes (At1g80240 and At5g25460, designated as DGR1 and DGR2, respectively) to be sensitive to it. In this work, leaves from wild-type Arabidopsis were fed with d-glucose, l-galactose, l-GalL and AsA, and the expression level of the At1g80240 and At5g25460 genes showed a specific response to l-GalL, but not to the other supplements despite the increases of the tissue AsA contents. Analysis of promoter-ß-glucuronidase (GUS) transgenic plants showed the two genes to be complementarily expressed at the root apex and in the rest of the root excluding the apex, respectively, in both young and old seedlings, and to be expressed at the leaf primordia. The GUS activity under the control of the At5g25460 promoter was high in the cotyledon and leaf veins of young seedlings. These findings were consistent with the results of quantitative real-time PCR. Interestingly, the T-DNA insertion mutant of At5g25460 (SALK_125079) displayed shorter roots and smaller rosettes than Col-0; however, no phenotypic difference was observed between the T-DNA insertion mutant of At1g80240 and the wild type. This is the first report on the expression and functional analysis of these two DUF642 family genes, with the results revealing the contribution of DGR genes to the development of Arabidopsis.

Assessment of Mulberry Silkworm Pupae and African Palm Weevil larvae as alternative protein sources in snack fillings.

The search for alternative food sources especially protein to meet the nutritional demand of the projected 9 billion world population by 2050 is now critical. Edible insect is an alternative source of protein in many African and Asian cuisines where beef, pork and chicken are perceived to be relatively expensive. The current study evaluates Mulberry Silkworm Pupae (MSP) and African Palm Weevil larvae (APW) as substitute to the mainstream proteins in snacks fillings, and also assessing the consumer acceptability of the new products. The chemical composition showed that MSP is higher in protein and soluble fibre contents while APW is higher in crude fat, crude fibre, zinc, manganese and calcium contents. The cooked edible insects were rich in both essential and non-essential amino acids. When used as fillings for snacks, the protein content of the snacks produced with APW and MSP compared favourably well with the snacks produced with beef fillings. The fat contents of the snacks were 18 % lower than those of snacks made with beef fillings. The mineral contents of the snack with APW were significantly higher than the other samples. There was no significant difference in the taste and overall acceptability of samosa snack produced with beef, APW and MSP. African palm weevil larvae and Mulberry silkworm pupae could serve as alternative sources of protein in the production of snacks and cuisines, and a viable source of income generation.

Increase in ascorbate content of transgenic tobacco plants overexpressing the acerola (Malpighia glabra) phosphomannomutase gene.

Phosphomannomutase (PMM; EC 5.4.2.8) catalyzes the interconversion of mannose-6-phosphate to mannose-1-phosphate in the Smirnoff-Wheeler pathway for the biosynthesis of l-ascorbic acid (AsA). We have cloned the PMM cDNA from acerola (Malpighia glabra), a plant containing an enormous amount of AsA. The AsA contents correlate with the PMM gene expression of the ripening fruits and leaves. The PMM activities in the leaves of acerola, tomato and Arabidopsis correlate with their respective AsA contents. Transgenic tobacco plants overexpressing the acerola PMM gene showed about a 2-fold increase in AsA contents compared with the wild type, with a corresponding correlation with the PMM transcript levels and activities.

Transcriptome profiling of four candidate milk genes in milk and tissue samples of temperate and tropical cattle.

The expression of four genes involved in milk regulation and production in bovine milk and tissue samples profiled using quantitative PCR to identify differential gene expression. Our goal focussed on the differential mRNA expression of milk genes (KCN, PRL, BLG and PIT-1) in milk samples and different tissues from four different breeds of ecologically adapted and geographically separated cattle species. The mRNA expression identified the four milk genes under studied most upregulated in mammary gland and milk samples as compared with other tissues. The expression of PIT-1 gene in the brain identified to have influenced the expression of PRL and K-CN in the mammary and milk samples. Among the four genes, PRL had the highest mRNA expression (144.19-fold change) in Holstein followed by K-CN with 100.89-fold change, while the smallest relative expression for most genes in this study are in the range from 0.79 to 7.35-fold difference. White Fulani cattle was identified to have a higher expression for K-CN, PRL and BLG compared with Angus and Ndama cattle, while Holstein cattle is on top of the list on the basis of the gene expression and gene regulation for all the four genes in this study. Also, White Fulani and Holstein are in the same cluster based on their mRNA expression for milk genes. Our data showed the first evidence of the molecular identification of indigenous White Fulani cattle ofhaving potential for higher milk production.

Cloning and expression of GDP-D-mannose pyrophosphorylase gene and ascorbic acid content of acerola (Malpighia glabra L.) fruit at ripening stages.

Acerola (Malpighia glabra L.) is one of the richest natural sources of L-ascorbic acid (AsA; vitamin C). GDP-D-mannose pyrophosphorylase (GMP; EC 2.7.7.13) was found to play a major role in the proposed AsA biosynthetic pathway in plants, considering that Arabidopsis vtc1-1 mutant with point mutation in this gene has a highly reduced AsA content. GMP cDNA was isolated from acerola fruits, designated MgGMP, using rapid amplification of cDNA ends (RACE), and its expression was monitored during fruit ripening. The full-length cDNA was found to have an ORF of 1083bp encoding a polypeptide of 361 amino acids. In silico analysis of the predicted amino acid sequence showed a pI of 6.45 and molecular mass of 39.7kD. MgGMP showed over 80% amino acid sequence identity with other plant GMP homologues. The phylogenetic tree shows the close relation of MgGMP to the GMP of other plants as against those from parasite, yeasts and mammals. Southern analysis indicated that M. glabra contains not less than two copies of GMP genes. Northern blot analysis showed the transcript abundance of MgGMP in all the organs of acerola examined, with the fruit having the highest expression. The relative transcript abundance of MgGMP mRNA levels in the fruits changes as the ripening process progresses, with the unripe green fruits having the highest relative mRNA level, and the lowest was found in the fruits at advanced ripening stage. A strong correlation was also observed between the relative MgGMP mRNA levels and the AsA contents of acerola during fruit ripening.

Effects of thermal processing on the nutritional and functional properties of defatted conophor nut (Tetracarpidium conophorum) flour and protein isolates.

Conophor nut (Tetracarpidium conophorum) was processed using different heat treatments to explore its full potential as food ingredients. The raw, boiled, and toasted nuts were defatted and the proteins isolated by alkaline solubilization and isoelectric precipitation. The variously processed nuts were analyzed for the proximate and amino acid compositions, and functional properties. The protein contents of the isolate ranges between 86.86 g/100g and 87.74 g/100 g, about 1.5-fold higher than those of the defatted flour samples. The essential amino acids of the isolates ranged between 40.57%-41.55%. Glutamic acid, aspartic acid, and arginine were the most predominant amino acids, while methionine and lysine were the first and second limiting amino acids, respectively. The protein efficiency ratio, biological values as well as the functional properties of the proteins were improved with processing. These properties may enhance the potential use of conophor nut protein isolates as high-quality protein ingredient in food systems.

Development of functional beverages from blends of Hibiscus sabdariffa extract and selected fruit juices for optimal antioxidant properties.

The demand for functional foods and drinks with health benefit is on the increase. The synergistic effect from mixing two or more of such drinks cannot be overemphasized. This study was carried out to formulate and investigate the effects of blends of two or more of pineapple, orange juices, carrot, and Hibiscus sabdariffa extracts (HSE) on the antioxidant properties of the juice formulations in order to obtain a combination with optimal antioxidant properties. Experimental design was carried out using optimal mixture model of response surface methodology which generated twenty experimental runs with antioxidant properties as the responses. The DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] radical scavenging abilities, ferric reducing antioxidant potential (FRAP), vitamin C, total phenolics, and total carotenoids contents of the formulations were evaluated as a test of antioxidant property. In all the mixtures, formulations having HSE as part of the mixture showed the highest antioxidant potential. The statistical analyzes, however, showed that the formulations containing pineapple, carrot, orange, and HSE of 40.00, 16.49, 17.20, and 26.30%, respectively, produced optimum antioxidant potential and was shown to be acceptable to a research laboratory guidance panel, thus making them viable ingredients for the production of functional beverages possessing important antioxidant properties with potential health benefits.

Processing Effects on the Antioxidant Activities of Beverage Blends Developed from Cyperus esculentus, Hibiscus sabdariffa, and Moringa oleifera Extracts.

The discovery of bioactive compounds in foods has changed the dietary lifestyle of many people. Cyperus esculentus (tigernut) is highly underutilized in Africa, yet tigernut extract is highly profitable in Europe. This study aims to add value to tigernut extract by revealing its health benefits and food value. In this study, tigernut tubers were germinated or roasted and the extracts were combined with Moringa oleifera extract (MOE) or Hibiscus sabdariffa extract (HSE) and spiced with ginger to produce functional drinks. The drinks were evaluated for physicochemical characteristics, sensory parameters, and antioxidant potentials. The total phenolic content of each beverage was measured by the Folin-Ciocalteu method, and the antioxidant activity of each beverage was determined by the 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid assays. The beverages from the germinated tigernut extracts had the highest titratable acidity and the lowest pH, while beverages containing the roasted tigernut extract had the highest ∘Brix. Germination and roasting significantly enhanced the total phenolic content of the drinks. The beverage containing HSE and germinated tigernut extract had a total phenolic content of 45.67 mg/100 mL gallic acid equivalents, which was significantly higher than the total phenolic content of all other samples. The DPPH inhibition activity of the beverages prepared with germinated tigernut extracts was significantly higher than the DPPH inhibition activity of the beverages prepared with fresh tigernut extract. The taste and overall acceptability of drinks containing the roasted tigernut extract were preferred, while the color and appearance of drinks with the germinated samples were preferred. Roasting or germinating tigernuts before extraction and addition of MOE or HSE extracts is another way to add value and enhance the utilization of tigernuts.

Gene expression of monodehydroascorbate reductase and dehydroascorbate reductase during fruit ripening and in response to environmental stresses in acerola (Malpighia glabra).

Acerola (Malpighia glabra) is an exotic fruit cultivated primarily for its abundant ascorbic acid (AsA) content. The molecular mechanisms that regulate the metabolism of AsA in acerola have yet to be defined. Monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) are key enzymes of the ascorbate-glutathione cycle that maintain reduced pools of ascorbic acid and serve as important antioxidants. cDNAs encoding MDHAR and DHAR were isolated from acerola using RT-PCR and RACE. Phylogenetic trees associated acerola MDHAR and DHAR with other plant cytosolic MDHARs and DHARs. Expressions of the two genes correlated with their enzymatic activities and were differentially regulated during fruit ripening. Interestingly, MDHAR expression was only detected in overripe fruits, whereas the transcript level of DHAR was highest at the intermediate stage of fruit ripening. Under dark conditions, there was a sharp and significant decline in the total and reduced ascorbate contents, accompanied by a decrease in the level of transcripts and enzyme activities of the two genes in acerola leaves. MDHAR and DHAR transcripts and enzyme activities were significantly up-regulated in the leaves of acerola under cold and salt stress conditions, indicating that expression of both genes are transcriptionally regulated under these stresses.

Gene expression of ascorbic acid biosynthesis related enzymes of the Smirnoff-Wheeler pathway in acerola (Malpighia glabra).

The Smirnoff-Wheeler (SW) pathway has been proven to be the only significant source of l-ascorbic acid (AsA; vitamin C) in the seedlings of the model plant Arabidopsis thaliana. It is yet uncertain whether the same pathway holds for all other plants and their various organs as AsA may also be synthesized through alternative pathways. In this study, we have cloned some of the genes involved in the SW-pathway from acerola (Malpighia glabra), a plant containing enormous amount of AsA, and examined the expression patterns of these genes in the plant. The AsA contents of acerola leaves were about 8-fold more than that of Arabidopsis with 5-700-fold higher mRNA abundance in AsA-biosynthesizing genes. The unripe fruits have the highest AsA content but the accumulation was substantially repressed as the fruit transitions to maturation. The mRNAs encoding these genes showed correlation in their expression with the AsA contents of the fruits. Although very little AsA was recorded in the seeds the mRNAs encoding all the genes, with the exception of the mitochondrially located L-galactono-1,4-lactone dehydrogenase, were clearly detected in the seeds of the unripe fruits. In young leaves of acerola, the expression of most genes were repressed by the dark and induced by light. However, the expression of GDP-D-mannose pyrophosphorylase similar to that encoded by A. thaliana VTC1 was induced in the dark. The expressions of all the genes surged after 24h following wounding stress on the young leaves. These findings will advance the investigation into the molecular factors regulating the biosynthesis of abundant AsA in acerola.

Analysis of GDP-D-mannose pyrophosphorylase gene promoter from acerola (Malpighia glabra) and increase in ascorbate content of transgenic tobacco expressing the acerola gene.

GDP-D-mannose pyrophosphorylase (GMP) is an important enzyme in the Smirnoff-Wheeler's pathway for the biosynthesis of ascorbic acid (AsA) in plants. We have reported recently that the expression of the acerola (Malpighia glabra) GMP gene, designated MgGMP, correlates with the AsA content of the plant. The acerola plant has very high levels of AsA relative to better studied model plants such as Arabidopsis. Here we found that the GMP mRNA levels in acerola are higher than those from Arabidopsis and tomato. Also, the transient expression of the uidA reporter gene in the protoplasts of Nicotiana tabacum cultures showed the MgGMP gene promoter to have higher activity than the cauliflower mosaic virus 35S and Arabidopsis GMP promoters. The AsA content of transgenic tobacco plants expressing the MgGMP gene including its promoter was about 2-fold higher than that of the wild type.