Development of a Protein-rich Composite Sorghum-Cowpea Instant Porridge by Extrusion Cooking Process

To develop an instant high protein porridge, various ratios of sorghum and cowpeas were extruded at 130 and 165 °C and a water content of 200 g/kg using a twin-screw extruder. An increased proportion of cowpeas resulted in an increase in protein content, nitrogen solubility index (NSI), yellow colour, water absorption (WAI) and solubility (WSI) indexes and in a decrease in total starch (TS), enzyme-susceptible starch (ESS), expansion ratio (ER), and porridge firmness. The higher extrusion temperature gave lower NSI, TS and WAI. ESS, ER and WSI increased with severity of heat treatment. The composite of 50% sorghum and 50% cowpeas extruded at 130 °C was the most similar to a commercial instant maize-soya composite porridge in terms of composition and functional properties. A serving of 100 g would contribute 28% of the recommended dietary allowance (RDA) for protein. This represents a 110% increase in the protein RDA compared to sorghum only.     

Bioactive phenolic compounds of cowpeas (Vigna sinensis L). Modifications by fermentation with natural microflora and with Lactobacillus plantarum ATCC 14917

In this work we have determined the phenolic composition of raw cowpeas (Vigna sinensis L) of the variety Carilla by HPLC/PAD/MS and have studied the effect of fermentation, both spontaneous and with Lactobacillus plantarum ATCC 14917, on the phenolic compounds. This variety contains mainly ferulic and p‐coumaric acids esterified with aldaric acids, together with the cis and trans isomers of the corresponding free acids. Hydroxybenzoic acids such as gallic, vanillic, p‐hydroxybenzoic and protocatechuic were also found, along with flavonols such as a myricetin glucoside, mono‐ and diglycosides of quercetin and a quercetin diglycoside acylated with ferulic acid. Fermentation, both spontaneous and inoculated, modifies the content of phenolic compounds, but differently in each case. The antioxidant activity as free radical‐scavenging activity has also been evaluated. Fermentation followed by heating has been shown to be a very effective process to increase the functionality of this variety of V sinensis. For this reason, this cowpea variety could be used as an ingredient to obtain high value‐added flours. Copyright © 2004 Society of Chemical Industry     

Gross composition,amino acid,phytic acid and trace element contents of thirteen cowpea cultivars and their nutritional significance

Thirteen cultivars of cowpea (Vigna unguiculata (L) Walp) were analysed for their proximate composition, amino acid, trace element and phytic acid contents. Crude protein values ranged from 206·8 to 283·8 g kg^?1 DM. The mean contents (g kg^?1) of other major nutrients were ether extract, 18·6; ash, 38·8; total dietary fibre, 121·8 and carbohydrates, 573·4. When compared with the provisional amino acid scoring pattern of FAO, all cultivars were low in methionine and high in lysine, isoleucine, leucine and phenylalanine plus tyrosine. Values for threonine and valine were variable compared with the pattern. The range of values for the chemical score was 0·61–0·74. Phytic acid values ranged from 5·10 to 10·27 g kg^?1, and the phytate: zinc molar ratios were all higher than that (15:1) above which zinc deficiency can be induced. Most of the trace elements showed wide variation in their occurrence among the cultivars. The values for zinc and iron showed less variation. The toxic elements mercury and selenium were present in varying amounts in more than half of the cultivars while tin was found in only one variety.     

雪莲菌发酵豇豆工艺优化及其挥发性风味成分分析

利用雪莲菌对豇豆进行发酵,以感官评分和总酸含量为评价指标,采用单因素和正交试验对发酵工艺进行优化;并采用高效液相色谱（HPLC）法和气相色谱—质谱联用（GC-MS）分析发酵前后风味物质的变化。结果表明,最佳发酵工艺条件为盐添加量4%,雪莲菌接种量1.5%,发酵温度25 ℃,发酵时间4 d ,此条件下感官评分为87分,总酸含量为3.40 g/kg。雪莲菌发酵后共检出72种挥发性风味物质,与原料相比,新产生了56种挥发性风味物质。除醛类物质外,其他挥发性风味物质相对含量均增加,且醇类和酯类含量较高。与自然发酵相比,雪莲菌发酵后的挥发性物质种类和含量也较高。     

Effect of milling and preparation method on the physical properties and quality of moin-moin (steamed paste)

ABSTRACT:  Moin-moin is steamed cowpea paste native to Nigeria. This product is classified as a protein/starch gel with the dominate portion of the gel network consisting of cowpea starch. Moin-moin was prepared from starting materials (cowpea meal and cowpea flour) and compared to moin-moin prepared from dry, whole, undecorticated cowpea seeds. Texture profile measurements showed that moin-moin made from cowpea flour (small particle size) formed a firmer structure when compared to moin-moin made from either cowpea meal or whole, dry cowpea seeds. Starting materials with smaller particle sizes and longer cooking times produced stickier moin-moin. The cowpea solids to water ratio was shown to affect the firmness of moin-moin, where a 3.75:1 ratio of solids to water produced a firmer product than other concentrations. Generally, color was unaffected across treatment regimens as identified by an expert sensory panel, although instrumental color measurements showed significant differences for hue angle and chroma. This study demonstrated that the particle size of this food ingredient contributes significantly to its functionality in food formulations.     

In vitro and in vivo digestibility of the albumin and globulin fractions of eight Brazilian cowpea [Vigna unguiculata (L) Walp] cultivars

Cowpea (Vigna unguiculata) is a very important crop for people living in the north‐east of Brazil where it constitutes the principal source of protein and carbohydrate. In this study, it was observed that the in vitro digestibility of the seed albumin and globulin fractions extracted from eight Brazilian cowpea cultivars was high when treated with pepsin but resistant to degradation by trypsin or chymotrypsin even after 3 h of treatment. When the albumin and globulin fractions were given to rats by intragastric intubation it was observed that intact proteins or their fragments were immunodetected in the faeces. Immunohistochemical analyses of the gut sections of these rats showed that a proportion of the albumin fraction (or its fragments), but not the globulin one, was bound to the brush border enterocytes in the duodenum. Thus the incomplete enzymatic degradation of both globulin and albumin fractions as well as the albumin binding to the gut may have a bearing upon the growth depression, malabsorption and diarrhoea observed on rats fed on cowpea seeds. Copyright © 2004 Society of Chemical Industry     

Gamma irradiation of cowpea (Vigna unguiculata L. Walp) seeds: effect on colour,cooking quality and pasting characteristics

Cowpea seeds were treated to various gamma irradiation doses, and their colour, cooking quality and pasting properties studied. Irradiation at 50 kGy resulted in significant browning (indicated by decreases in L colour value) of cowpea seeds. At 2 and 10 (but not at 50) kGy, irradiation led to significant reduction in cooking time of cowpea seeds possibly through irradiation‐induced degradation of starch and pectic substances (indicated by decreases in peak and final viscosities) leading possibly to enhanced heat and mass transfer within the seed cotyledon and cell wall, respectively. At 50 kGy, the cooking time of cowpea seeds was prolonged significantly owing possibly to extensive polymer cross‐linking occurring within the seeds at this high dose. Splitting of cowpea cotyledons during cooking decreased significantly at 50 kGy, but was unaffected at 2 and 10 kGy. Irradiation resulted in significant leaching of nutrients from cowpea seeds during cooking in a dose‐dependent manner.     

Effect of Milling Method (Wet and Dry) on the Functional Properties of Cowpea (Vigna unguiculata) Pastes and End Product (Akara) Quality

ABSTRACT: Akara, deep-fat fried cowpea paste, is a very popular snack and breakfast food in Africa. Traditional cowpea paste processed by wet-milling of soaked, decorticated seeds exhibited excellent foaming ability, high water-holding capacities (WHC), and low hardness value for akara. Intense dry-milling that generated a fine flour adversely affected its functionality and akara-making quality. Wet-milling of hydrated cowpea meal significantly improved its foamability (as indicated by reduction in specific gravity) and WHC but showed only a marginal improvement in akara texture.     

沙藏对减轻豆角冷害效果的研究

豆角于冷害条件下(2℃)贮藏,通过测定其Vc含量、色差以及总抗氧化活性的变化,研究沙藏对减轻豆角低温冷害的效果。结果表明,沙藏可以减轻冷害的程度,维持豆角的品质,其中以4％含水量的沙子沙藏效果最好。