Plant Foods for Human Nutrition (v.54, #2)
Agglutinating activity of alcohol-soluble proteins from quinoa seed flour in celiac disease
by M. De Vincenzi; M. Silano; R. Luchetti; B. Carratù; C. Boniglia; N.E. Pogna (pp. 93-100).
The edible seeds of the quinoa plant contain small quantities of alcohol-soluble protein which, after peptic-tryptic digestion, are unable to agglutinate K562(s) cells. When separated by affinity chromatography on sepharose-6B coupled with mannan, peptic-tryptic digest separated in two fractions. Fraction B peptides (about 1% of total protein) were shown to agglutinate K562(s) cells at a very low concentration, whereas peptides in fraction A and in the mixed fraction A+B were inactive, suggesting that fraction A contains protective peptides that interfere with the agglutinating activity of toxic peptides in fraction B.
Keywords: Amino acids; Celiac disease; Cells; Cereals; Prolamines; Quinoa seeds
Chemical evaluation of waste from Thaumatococcus danielli (Benth) processing
by B.O. Elemo; O.S. Oladimeji; O.B. Adu; O.I. Olayeye (pp. 101-108).
Three different batches of Thaumatococcus danielli (Benth) fruits were collected at different fruiting seasons. The proximate compositions of the pericarp and seeds were determined on a dry weight basis. Partial characterization of the lipid extract was carried out and tannin content determined. The average moisture, ash and lipid contents of the pericarp were higher (89.2 ± 4.17%, 20.7 ± 1.10% and 11.6 ± 1.23%, respectively) than those of the seed (31.2 ± 4.66% 9.1 ± 0.71% and 8.2 ± 1.64%, respectively). Crude protein and total carbohydrate were, however, higher in the seed (9.5 ± 4.38% and 69.4 ± 11.52%, respectively) than in the pericarp (4.5 ± 2.21% and 6.3 ± 3.94%, respectively). The dietary fiber contents of both pericarp and seed were high. Starch content was very low in the pericarp (0.4 ± 0.0%) compared to the seed (66.28 ± 9.21%). Tannin content in the pericarp and seeds was 12.1 ± 1.52 mg/g and 21.9 ± 2.28 mg/g, respectively. The oil extracted from both pericarp and seeds was light-yellow in color and slightly solid at room temperature. Unsaturation level of T. danielli oil was low, while free fatty acids were high. The results obtained suggested that T. danielli waste could potentially be a raw material in livestock feed formulation.
Keywords: Chemical composition; Food production; Potential application; Thamatococcus danielli wastes
Biochemical changes in wheat during storage at three temperatures
by Zia-Ur Rehman; W.H. Shah (pp. 109-117).
Biochemical changes in wheat grains stored at 10, 25 and 45 °C for six months were studied. A significant decrease in pH and an increase in titratable acidity was observed during storage of wheat grains at 25 °C and 45 °C. Moisture contents of wheat grains decreased by 15% at 25 °C and 26% at 45 °C during six months of storage. A significant decrease in water soluble amylose (20–28%) along with an increase in insoluble amylose contents (7.6–17%) were observed during storage at 25 and 45 °C. Amylase activity of the samples showed a decrease as the storage progressed. Total soluble sugars increased by 9% at 10 °C and 12% at 25 °C; a 37% decrease was observed after six months storage at 45 °C. Total available lysine decreased by 18.0% and 22.6% at 25 and 45 °C, respectively, after six months storage. In vitro protein digestibility of wheat grains decreased by 5.00% at 25 °C and 10.28% at 45 °C during six months of storage. However, no significant biochemical changes occurred during storage at 10 °C.
Keywords: Biochemical changes; Storage temperature; Wheat grains
Measurement of the relative sweetness of stevia extract, aspartame and cyclamate/saccharin blend as compared to sucrose at different concentrations
by H.M.A.B. Cardello; M.A.P.A. Da Silva; M.H. Damasio (pp. 119-129).
Special diets are used to mitigate many human diseases. When these diets require changes in carbohydrate content, then sweetness becomes an important characteristic. The range of low-calorie sweeteners available to the food industry is expanding. It is essential to have an exact knowledge of the relative sweetness of various sweeteners in relation to different sucrose concentrations. The objective of this study was to determine the variation on the relative sweetness of aspartame (APM), stevia [Stevia rebaudiana (Bert.) Bertoni] leaf extract (SrB) and the mixture cyclamate/saccharin – two parts of cyclamate and one part of saccharin – (C/S) with the increase in their concentrations, and in neutral and acid pH in equi-sweet concentration to 10% sucrose, using magnitude estimation. Sweetness equivalence of SrB in relation to sucrose concentrations of 20% or higher and of APM and C/S to sucrose concentrations of 40% or higher could not be determined, because a bitter taste predominated. The potency of all sweeteners decreased as the level of sweetner increased. In equi-sweet concentration of sucrose at 10%, with pH 7.0 and pH 3.0, the potency was practically the same for all sweeteners evaluated.
Keywords: Aspartame; Cyclamate; Saccharin; Sensory analysis; Stevia; Sweetness
Use of two varieties of hard-to-cook beans (Phaseolus vulgaris) and cowpeas (Vigna unguiculata) in the processing of koki (a steamed legume product)
by C.M.F. Mbofung; N. Rigby; K. Waldron (pp. 131-150).
Koki is a nutritious cowpea-based food product usually processed by steam cooking whipped cowpea (Vigna unguiculata) paste mixed with spices and palm oil. A study was carried out to investigate the effect of the partial replacement of cowpeas (CP) with hard-to-cook (HTC) beans on the chemical, nutritional and sensory characteristics of koki. Towards this objective, two varieties of beans – Phaseolus vulgaris (red kidney beans – RKB and mottled brown beans – MBB), each with the HTC defect, were separately incorporated into cowpea paste in the following Bean:CP ratios 0:100, 20:80, 30:70, 40:60, 50:50, 60:40 and processed into koki. Incorporation of dry HTC beans into cowpeas in the making of koki affected the bulking properties of the uncooked paste, the nutrient composition, essential amino acid content, antinutritional factors, digestibility as well as the sensory attributes of cooked koki. Sensory tests showed that a highly acceptable, nutritious and digestible koki can be processed from cowpeas partially replaced with dry HTC bean paste up to levels of about 40–50% depending on the variety of dry bean used.
Keywords: Antinutrient; Beans; Cowpea; Digestion; Hard-to-Cook; Koki; Nutrition; Sensory analysis
Quality attributes of fermented yam flour supplemented with processed soy flour
by O.K. Achi (pp. 151-158).
Pretreated soy flour was used to replace 10, 20, 30 and 40% of fermented yam flour as a protein supplement. The effect of the supplementation on the physicochemical and sensory properties of ‘amala’, a popular West African food made from rehydrated yam flour, was investigated. Blanching (10 min in boiling water) and subsequent fermentation (24 h) as pretreatment methods produced flour that was lighter in color than the unfermented samples. Protein content of the yam-soy mixture increased from 3.5% in the control to 19.7% for 40% soy fortification. Water binding capacity increased from 212.6 g/100 g for the yam flour control to 257.3 g/100 g for the blend with 40% soy flour. However, swelling capacity and solubility were adversely affected with increased soy flour addition as dough became sticky and soft. There was no significant difference in color, taste, flavor or overall acceptability when compared with the control up to 20% soy substitution. Dough with 20% soy flour is a possibility for increasing the protein content of yam flour in human feeding.
Keywords: Fermentation; Proximate composition; Sensory properties; Soy flour substitution; Weaning food; Yam flour dough
Calcium chloride sprays decrease physiological disorders following long-term cold storage of apple
by Ramdane Dris; Raina Niskanen (pp. 159-171).
Field experiments were carried out at the Horticultural Research Institute, and in five commercial apple orchards, located in southwest Finland including the Åland Islands during 1994 and 1995. The experimental cultivars were Melba, Raike, Red Atlas, Åkerö, Aroma, and Lobo. The treatments were untreated control and preharvest calcium chloride (CaCl2) sprays at Ca 2.0 g/l. Fruit samples were stored for two to six months at 2–4 °C and 85–95% RH. The percentage of the incidence of physiological disorders of stored apples was scored. Fruit macronutrients, firmness, diameter and juice titratable acidity and percentage of soluble solids were determined. Only a few nutrient effects in the flesh of the apple cultivars were a result of CaCl2 sprayings. Preharvest CaCl2sprays increased fruit firmness and the titratable acidity but decreased soluble solids, soluble solids/titratable acidity ratio, and the incidence of physiological storage disorders of some cultivars. When looking at the mean of all cultivars, CaCl2 sprayings increased titratable acidity and decreased soluble solids/titratable acidity ratio after four months of storage during 1995 and reduced the incidence of physiological disorders after three months of storage during 1994 and after four months of storage in 1995.
Keywords: Cultivars; Fruit firmness; Macronutrients; Soluble solids; Titratable acidity
Effect of Detarium microcarpum (Dm) and Mucuna flagellipes (Mf) gums on the quality of white bread
by J.C. Onweluzo; K. Leelavathi; P. Haridas Rao (pp. 173-182).
Incorporation of Detarium Microcarpum (Dm) and Mucuna flagellipes (Mf) water soluble polysaccharides (gums) at 0.0 to 0.5% levels in wheat flour was studied to evaluate their effect on the rheological properties of wheat flour dough and white bread quality. At all levels of incorporation, there were increases (p≤ 0.05) in water absorption of the dough. Doughs containing gums had higher (p≤ 0.05) mixing tolerance index than the control. Set back viscosities decreased by 4.0 RVU and 9.0 RVU with increased levels of Dm and Mf gum incorporation, respectively. Significantly (p≤ 0.05) higher oven spring occurred in all the gum substituted white bread when compared to the control. The 0.5% gum substituted breads had a significantly (p≤ 0.05) higher sensory score for crumb grain, texture but lower (p<0.05) crumb firmness than the control as determined instrumentally. Textural analysis after 5 days storage revealed that Dm and Mf gums improved moisture retention properties of the bread and reduced crumb firming tendency.
Keywords: Detarium microcarpum; Moisture retention; Mucuna flagellipes; Oven spring; Polysaccharide gums; White bread