EFFECTS OF PROCESSING METHODS ON THE PROTEIN QUALITY OF MUCUNA BEAN (MUCUNA PRURIENS L.)

Mucuna bean (Mucuna pruriens L.) is grown in many parts of Kenya as a green manure/cover crop. The bean contains a high content of crude protein. However, it remains a minor food crop due to the presence of anti-nutritional compounds such as 3,4-dihydroxy-L-phenylalanine (L-Dopa). The potential for utilization of mucuna bean as an alternative source of protein was evaluated by assessing the effect of various processing methods on its protein quality. Mucuna bean was processed to remove L-Dopa and other anti-nutritional compounds by different methods such as soaking, autoclaving, roasting, germination, and alkaline fermentation. Protein quality was determined by amino acid composition, in vitro and in vivo rat balance methodologies. All processing methods except roasting improved in vitro protein digestibility (IVPD). Soaking in acidic medium (pH 3.2) at 60°C for 48 hrs significantly improved IVPD (80.5%) and biological value (80.8) of mucuna bean protein. The content of essential amino acids met the recommended FAO/WHO reference requirements for 2-5 yr old except for tryptophan. However, true digestibility for processed bean diet was poor (58%) and protein digestibilitycorrected amino acid score (PDCAAS) low (0.4) compared to that of reference casein (1.0). This was attributed to both low sulphur amino acids content and possible presence of factors that affect protein hydrolysis such as phenolic compounds. Mucuna protein diet did not support growth of weanling rats indicating amino acids pattern incompatible with the needs of weanling rats. Histological examination of liver and kidney tissues revealed that consumption of processed mucuna bean as the only source of protein caused inflammation of the organs. This suggests possible presence of other antitoxins in processed bean even though mucuna bean diet contained the recommended safe level of residual L-Dopa (<0.1%). Processing mucuna bean by soaking in acidic medium (pH 3.2) at 60°C for 48 hrs improved protein quality. However, mucuna bean is not recommended as a sole protein in human diet

Nutritional quality and physicochemical properties of Mucuna bean (Mucuna pruriens L.) protein isolates

The potential for mucuna bean protein isolate (MBPI) application as functional ingredient in foods is unknown. In this study nutritional quality and physicochemical properties of MBPI were investigated. Bean samples were processed for L-dopa extraction in distilled water adjusted to pH 3.2 at 60°C for 48hr. MBPI was extracted at pH 9.0 and isoelectrically precipitated at pH 4.5. MBPI from raw and processed seed contained higher protein content (86.7 and 86.9% respectively) than soybean protein isolate (82.7%). Essential amino acids content of MBPI met FAO/WHO scoring pattern for 2-5 year-old. SDS-PAGE revealed four main polypeptide protein subunits of apparent MW of 11, 19, 36 and 98 kD in MBPI. MBPI exhibited high foam stability, emulsion activity and stability compared to soybean protein isolate. However, poor foam expansion, water and oil absorption capacity and dark colour (Hunter lab “L” value of 36.39) limits its potential as a functional food ingredient

Nutritional Composition of Kenyan Sorghum-pigeon Pea Instant Complementary Food

An instant complementary food product was developed by blending flours from two improved sorghum varieties, Gadam and Seredo, a local variety (kivila kya ivui) and one improved pigeon pea variety KAT 60/8. The effects of fermentation, germination and dehulling techniques on nutritional and anti-nutrient composition of the food were determined. Malted sorghum, fermented sorghum and steam cooked dehulled pigeon pea flours were prepared by appropriate processes. The flours were blended at three different ratios of 1:1, 2:1 and 5:1 (w/w, sorghum: pigeon pea). Untreated flour of both crops was also prepared and blended at the same ratios and used as control. Fermentation and malting increased the crude protein content significantly (P &lt; 0.05). Fermented sorghum flour blend was found to be the highest with 14.11%. Crude protein content differed significantly among the formulations; flour blended at the ratio of 1:1 had the highest with 14.91%. The antinutrients content of the instant complementary food was significantly reduced by fermentation and malting. The tannin and phytate content was least in fermented and malted food which had 2.25 mg/100g and 207.5 mg/100g respectively. Blending flours at the ratio of 1:1 was found to be the most effective at reducing the antinutrients contents. The macro elements (Ca and Mg) were found to be highest in formulation 1:1 which had 29.81 mg/100g and 44.86 mg/100g respectively. Micro element (Fe) Iron was found to be highest in food formulated at the ratio of 5:1 which had 11.87 mg/100g. The results suggest that fermentation, as a processing technique and blending sorghum and pigeon pea flours at the ratio of 1:1 using Gadam variety, can be used to effectively enhance the nutritional status of sorghum- pigeon pea instant complementary food with concomitant reduction of its anti-nutritional factors

AGRICULTURE AND BIOLOGY JOURNAL OF NORTH AMERICA Effect of drying on selected proximate composition of fresh and processed fruits and seeds of two pumpkin species

ABSTRACT Studies were conducted at Jomo Kenyatta University of Agriculture and Technology, Kenya to investigate the effect of drying on the proximate composition of crude fibre, crude fat and carbohydrates of two species of pumpkins namely, C. moschata and C. maxima in the year 2006. the treatments comprised fruits with rind and those without rind (fruit pulp), whole seeds and seed kernels, and raw and dry samples (flour). The experimental design was completely randomized and data analysis was by Genstat package. Proximate composition of raw C. moschata fruit with rind was 87.9% moisture (fresh weight), 4.9g/100g crude protein and 6.7g/100g crude ash. The corresponding values of C. maxima were 87.0/100g, 3.9g/100g and 6.9g/100g on dry weight basis. C. moschata with rind contained significantly (P &lt;0.05) higher crude fat than C. moschata seeds. The results also showed that there was significantly (P&lt; 0.05) more crude protein in C. maxima than C. moschata. Similar results were obtained for moisture content. The conclusion is that pumpkin seeds are rich in protein and both species of pumpkin contain high moisture content in their fruits, yielding a dry matter of approximately 12% on dehydration. Pumpkin seeds contain low moisture levels of 5.7% -6.1% making them be stored for longer duration.Pumpkin seeds are a better source of protein hence contributes substantially to the dietary human nutrition. Crude ash content of pumpkin fruits was higher than that for seeds showing that mineral intake in the diet can be enhanced by increasing the consumption of pumpkin fruits

Relationships Between Simple Grain Quality Parameters for the Estimation of Sorghum and Maize Hardness in Commercial Hybrid Cultivars

Grain hardness affects sorghum and maize processing properties especially for dry milling. A variety of simple grain quality parameters were assessed on 17 sorghum and 35 white maize hybrid cultivars grown in six and four locations, respectively, in South Africa. The purpose was to determine tests that can be used to distinguish hardness in commercial sorghum and maize. The grains were characterized by test weight (TW), thousand kernel weight (TKW), decortication with the tangential abrasive dehulling device (TADD), and kernel size. Maize was also characterized for susceptibility to breakage, stress cracking, and near-infrared transmittance (NIT) milling index. Principal component analysis showed that, in nontannin and tannin sorghums, TADD hardness and TW were closely correlated (P < 0.001). In maize, TADD hardness was closely correlated (P < 0.001) with NIT milling index and TW. Hence, TADD hardness and NIT milling index or TADD hardness and TW would be suitable for maize hardness evaluation. A combination of TADD hardness, TW, TKW, and kernel size >3.35 mm can be used together to select sorghum grain for hardness. It thus appears that TADD hardness is an excellent method of estimating both sorghum and maize hardness that can be applied for routine batch analysis and cultivar evaluation.The International Sorghum and Millet Collaborative Research Support Program (INTSORMIL).http://www.nonprofitjournals.org/journals/cereal_chemistry.ht

Functional properties of protein isolate obtained from physic nut (Jatropha curcas L.) seed cake

Physic nut (Jatropha curcas L.) protein isolate was successfully achieved from physic nut seed cake by an alkaline extraction and followed by an isoelectric precipitation. The protein isolate had small amounts of phorbol esters, phytic acid, and saponin without any lectin. Its minimum and maximum solubility were at pH 4.0 and 12.0, respectively. Its water and oil binding capacities were 3.22 g water/g protein and 1.86mL oil/g protein, respectively. Its foaming capacity and emulsion activity showed high values in a range of basic pHs. Its foaming and emulsion stability values decreased with increasing time and exhibited high levels under basic pH conditions. Physic nut protein isolate had unique functional properties in water binding capacity, emulsion activity, and emulsion stability indicating an important role in food systems. It may be applied to salad dressing, mayonnaise, sausage, and meat products. Therefore, physic nut seed cake has a potential to be exploited as a novel source of functional protein for food or feed applications. © KoSFoST and Springer 2011