Showing papers in "African Journal of Food Science in 2018"

Shelf life and quality of tomato (Lycopersicon esculentum Mill.) fruits as affected by different Packaging Materials

Abstract: Tomato (Lycopersicon esculentum Mill.) is one of the most widely cultivated and extensively consumed horticultural crops in Ethiopia. Tomato has a limited shelf life at ambient conditions, is highly perishable fruit and it changes continuously after harvesting. There are many postharvest technologies that extend the marketable life of fruits and vegetables. The study was to evaluate the effect of packing materials on shelf-life and quality of tomato fruit at Samara, Northeastern rift valley of Ethiopia. Three types of packaging material were taken, that is, low density perforated and non-perforated polyethylene bag, carton and without packaging as a control. Physiological weight loss, decay percentage, color score, overall acceptability and percentage marketability were assessed for every three days of storage. The result revealed that packaging had a significant effect on physiological weight loss, decay percentage, color score, overall acceptability and marketability. The lowest physiological weight loss of 0.29 and 1.72% was recorded from non-perforated polyethylene bag at 3 and 6 days of storage, respectively; further increase in the storage period with the lowest physiological weight loss (24.57%) was recorded from perforate polyethylene bag. Moreover, the lowest (0.00%) decay percentage and the highest (60%) marketability were recorded from perforated polyethylene bag on day 9 of storage. Decay loss of tomato fruits at the end of storage was much (60%) higher on non-perforated polyethylene bag than the perforated and carton (0.00%). Color and overall acceptability score of tomato fruit was also maximum on perforated polyethylene bag and the lowest was obtained from control treatment at the end of storage. It can, thus, be concluded that packaging of tomato fruits in perforated polyethylene bags resulted in extending storage-life with better-quality of the produce in samara area. Key words: Tomato fruit, packaging material, storage life, quality.

Enhancing the retention of -carotene and vitamin C in dried mango using alternative blanching processes

Abstract: The effects of microwave (MW) dry blanching of mango in comparison with conventional water blanching and blanching in closed plastic bags prior to hot air drying (70°C) were evaluated on the retention of vitamin C and β-carotene and on the activity of polyphenol oxidase (PPO) and ascorbic acid oxidase (AAO) enzymes. Blanching conditions for MW and water blanching were 2 min at 90°C high temperature and short time (HTST) or for 10 min at 70°C low temperature and low time (LTLT). PPO was completely inactivated by the blanching treatments, while low AAO activity remained. High retentions (~100%) of vitamin C were found in dried mango after blanching treatments HTST with MW and blanching in closed plastic bags, while lower retention was observed after LTLT with MW (81.8 ± 4.5%), and conventional water blanching 86.7 ± 2.6% (HTST) and 78.6 ± 2.5% (LTLT). Blanching resulted in partial oxidation of L-AA into dehydroascorbic acid (DHAA). Lower retention of all-trans-β-carotene was obtained in MW and HTST water blanched dried mango (82 to 90%) compared with LTLT water blanched dried mango (~100%). In all dried blanched mango samples the levels of 13-cis-β-carotene isomer increased. A slight darkening of colour was observed only in conventional blanched mango samples. Key words: Microwave heating, mango, β-carotene, vitamin C, ascorbic acid oxidase.

Quality attributes of homemade tomato sauce stored at different temperatures

Abstract: Tomato (Lycopersicon esculentum) is processed into different products including tomato sauce. The aim of this study was to determine the quality attributes of homemade tomato sauce during storage at 6 and 30°C for 8 weeks. At 4 weeks, there were no significant changes in sensory attributes during storage at both 6 and 30°C. There were significant differences (PE‚0.05) of sensory attributes after 6 weeks. Sauce stored at 30°C had higher microbial load than at 6°C. Both sensory mean scores and pH were inversely related to microbial growth. Therefore, the shelf-life of homemade tomato sauce could be increased at low temperature (6°C). Key words: Homemade tomato sauce, storage temperatures, sensory, attributes.

Production and functional property of maize-millet based complementary food blended with soybean

Abstract: Traditional complementary foods are mainly based on cereal grains which when cooked get gelatinized and swollen thereby making the diet viscous and bulky for infants and young children. This study was carried out to investigate the effect of fermentation, germination, and roasting methods on the functional properties of maize-millet-soybean mix with a view to producing less bulky and nutrient dense complementary food. Fermented, germinated, roasted, and untreated (control) grains were dried in an air oven at 55°C for 48 h to 10% moisture content, milled and sieved separately into fine flours (450 microns). Four complementary food samples were formulated and analyzed for wettability, dispersibility, water absorption capacity, swelling power, solubility index and pasting properties. Results showed that fermentation, germination, or roasting methods significantly (p<0.05) affect functional property of the complementary food samples. The swelling power of fermented sample was higher, while solubility of germinated sample was higher than other samples. The water absorption capacity of the complementary food samples ranged from 1.27 in germinated maize-millet-soybean to 1.61 in control sample. Fermented sample had the highest peak, trough and final viscosities, while germinated sample had the least. The study showed that germination significantly reduced water holding capacity and swelling power of the complementary food, and is recommended for producing nutrient dense complementary from maize-millet-soybean mix. Key words: Complementary food, gelatinize, functional property, processing method.

Physicochemical properties of starches extracted from local cassava varieties with the aid of crude pectolytic enzymes from Saccharomyces cerevisiae (ATCC 52712)

Abstract: Starches extracted from root mashes of the Nkabom, Esam Bankye, Bankyehemaa, Doku Duade and Afisiafi cassava varieties, with the aid of (crude) pectolytic enzymes from Saccharomyces cerevisiae pectolytic were analysed to compare effects of (pectolytic) enzyme technology on the physicochemical properties of the extracted starches. This was to help establish the extent to which varietal differences affect application of the technology and to inform the possible domestic or industrial application of the ensuing starches. Enzyme treatment generally did not affect the protein, fiber and ash content of the starches. However, it significantly increased moisture content, starch granule sizes, water binding capacity and swelling power of the starches in most the varieties; pH of the extruded starches were also significantly decreased and the starches’ colour was also significantly made lighter by the technology. Despite the general trends observed, the technology was found to impact physicochemical properties of some varieties more than others. The work therefore showed that the technology is variety-sensitive and could influence starch utility. Key words: Amylolysis, cassava varieties, crude pectolytic enzymes, endogenous amylase, starch physicochemical properties.

Assessment of entomophagy in Abidjan (Cote Divoire, West Africa)

Abstract: In order to assess the contribution of edible insects to the efforts for combatting food insecurity and poverty in Cote d’Ivoire, a survey aimed at identifying edible insects in Cote d’Ivoire was conducted from August 2014 to August 2015 in three communes in the city of Abidjan (Abobo, Adjame and Yopougon). Four hundred and seventy-two people were interviewed at random. The results revealed that 59.72% of the respondents consume insects against 40.27% who do not consume them. This study has helped to identify nine edible insect species belonging to eight families and five orders. The species Imbrasia oyemensis (Lepidoptera, Satunidae) and Macrotermes subhylinus (Isoptera, Macrotermitidae) are widely consumed due to their availability in markets. The species Rhyncophorus phoenicis (Coleoptera, Curculionidae) or palm tree caterpillar is one of the most prized by 40% of the surveyed population. The statistical analyses applied to the 365 people surveyed revealed that insect consumption is a function of the cultural area (X²=76.7; ddl= 4, p < 0.05) and the age ((X²=54.88, ddl=3; p < 0.05) of the consumers. In economic terms, insect trade remains a significant source of income in households having an average income estimated at 58,666.66±11216 FCFA per seller and per month. However, their availability in markets is seasonal. A mastery of the biology of these insects could ensure their permanent availability in markets. Key words: Edible insects, Abidjan, motivations, age, region, consumers.

Antioxidants activity of the cyanobacterium, Arthrospira (Spirulina) fusiformis cultivated in a low-cost medium

Abstract: Spirulina species are known to have a good nutritional profile and antioxidant properties against reactive oxygen species. However, little is known about the antioxidant contents and the scavenging ability of Arthrospira fusiformis, cultivated under various conditions. This study aimed at evaluating the content of antioxidants (total phenols, total flavonoids, β-carotene, and lycopene) and the activity of A. fusiformis produced using low-cost culture (LCMA) and standard culture (Zarrouk) media. The results revealed that A. fusiformis is rich in antioxidants and it possesses high scavenging and chelating activities. Interestingly, the LCMA was superior over the Zarrouk medium as it resulted in spirulina with a higher amount of antioxidants and lower EC50 values. In this context, production of natural antioxidants can be maximized through the use of cost-saving, inorganic culture medium. Key words: Arthrospira fusiformis, spirulina, total phenols, total flavonoids, carotenoids, scavenging activity, low-cost culture (LCMA) medium, Zarrouk medium.

Nutritional potential of underutilized gum arabic tree seeds (acacia nilotica) and locust bean seeds(Parkia biglobosa)

Abstract: Acacia nilotica seed (ANS) and Parkia biglobosa seed (PBS) are underutilised legume found to have health benefits and functional properties. This study determined nutrient composition of A. nilotica and P. biglobosa seeds. ANS and PBS were collected and processed properly for chemical analysis. The proximate, minerals, vitamins, essential amino-acids, and antinutrient composition were analyzed to ascertain nutritional attributes and its potential in promoting dietary diversity. The raw and fermented A. nilotica seeds contained in g/100 g, protein (12.88 to 15.38), fat (3.29 to 4.91), ash (5.24 to 6.84), dietary fibre (1.98 to 2.66) and available carbohydrate (69.63 to 71.73), while the FPB contained in g/100 g, protein (18.30), fat (9.20), ash (8.69), dietary fibre (2.61), and available carbohydrate (56.27). The fermented A. nilotica (FAN) seed contained all the nine (9) essential amino acids. The raw and fermented ANS contained in mg/100 g, iron (9.67 to 12.23), zinc (0.69 to 1.13), calcium (0.17 to 0.22), sodium (0.14-0.21) while the FPB seed contained 14.86, 1.59, 0.25, and 0.24, respectively. FAN and FPB contained in µg/100 g, vitamin A (148.79 and 197.81), vitamin E (15.90 and 24.69) and vitamin K (1.41 and 1.63), respectively. The levels of antinutrient factors in all the samples were not significant. Fermented A. nilotica seed contained adequate level of some micronutrients and essential amino acids. Consumption of the seed should therefore be promoted. Key words: Nutrient composition, dietary diversity, underutilized legumes, essential amino acid, functional properties, proximate composition, antinutritional factors.

Oxalate, phytate and nitrate content in African nightshade, spider plant and amaranths at different stages of maturity

Abstract: African indigenous green leafy vegetables play important role in income generation and subsistence; they are the cheapest and most readily available sources of important minerals and vitamins. On the other hand, they contain anti-nutritional factors that reduce availability of vital nutrients. This study was conducted to determine oxalates, phytates and nitrates content in commonly consumed Amaranths cruentus, Spider plant (Cleome gynandra) and African night shade (Solanum villosum) at 21, 28 and 35 days age of the plant harvest. Vegetables were planted on plots and harvested at 21, 28 and 35 days. At each stage, about 600±2 g of the edible part was harvested and standard chemical analyses procedures were followed to determine oxalate, phytate and nitrate contents. Using Statistical Product and Service Solutions (SPSS 20) data were analysed and results presented as simple means, ranges and standard deviations. Analysis of variance (ANOVA) with 5% level of significance was done to determine differences in the levels of nutrients between the vegetable varieties and three maturity stages. African nightshade Nduruma BG 16 had lowest oxalate concentrations (28.7 ± 0.1 mg/100 g) at maturity stage I while African nightshade Olevolosi SS 49 had the highest value (60.9 ± 0.9 mg/100 g) at maturity stage III. There was no particular trend for phytates in all maturity stages and in all varieties but amaranths Madiira AM 38 had exceptionally the highest values (0.7 ± 0.0 mg/100 g) at stage III of maturity. The highest nitrate content was 85.61.8 mg/100 g in Olevolosi SS 49 at maturity stage I, whereas the lowest value was 45.31.3 mg/100 g in amaranths Madiira AM 38 at stage III. There was a slight variation in antinutrients composition of the studied vegetables and the composition was generally very low. Key words: Antinutrients, indigenous vegetables, maturity stage, Tanzania.

Comparative assessment of some physico-chemical properties of seed oils of Parkia biglobosa and Monodora myristica with some commercial oils

Abstract: The demand for oils has increased in recent times as a result of industrial and nutritional processes. There is therefore the need to search for oils from different types of seeds. As part of an on-going work to search for alternate sources of oils, seed oils from Monodora myristica and Parkia biglobosa were extracted, analysed and some of their physicochemical properties were compared with those of vegetable and palm oils. The results show that seed oils of M. myristcia and P. biglobosa have some physicochemical properties comparable with those of the commercial oils and hence have great nutritional and industrial potentials. It is therefore recommended that more studies be undertaken for this abundant source of natural nutritious oil. Key words: Physicochemical properties, vegetable oils, Monodora myristica, Parkia biglobosa.

Chemical composition, functional and organoleptic properties of complementary foods formulated from millet, soybean and African locust bean fruit pulp flour blends

Abstract: This study was aimed at producing and evaluating the quality of complementary foods from millet, soybean and African locust bean fruit pulp. The millet, soybean and African locust bean fruits were obtained locally in Kaduna, Nigeria. These materials were separately cleaned, dried, milled and sieved into flours. The flours were mixed as follows: Sample A (60% millet, 10% soybean, 30% African locust bean fruit pulp), sample B (60% millet, 20% soybean, 20% African locust bean fruit pulp), Sample C (50% millet, 40% soybean, 10% African locust bean fruit pulp), sample D (50% millet, 30% soybean, 20% African locust bean fruit pulp), sample E (50% millet, 20% soybean, 30% African locust bean fruit pulp). The chemical composition, functional properties and sensory attributes were determined using standard methods. The moisture content of the food samples varied from 7.5 to 11%, protein ranged from 28.9 to 37.0%, fat from 3.1 to 5.1%, Ash ranged from 1.4 to 2.51%, crude fibre ranged from 2.0 to 3.2%, carbohydrate varied ranged from 47.0 to 52.1%. The energy values ranged from 351 to 381.9 kcal/g and appreciable amount of minerals were recorded. Calcium ranged from 128.0 to 165.0 mg/100 g, iron ranged from 3.2 to 5.8 mg/100 g and zinc ranged from 2.6 to 3.2 mg/100 g. The results of functional properties showed that bulk density ranged from 0.61 to 0.66 g/ml, water absorption capacity ranged from 1.89 to 2.31 g/g, swelling capacity ranged from 0.67 to 2.45% and least gelation ranged from 9.00 to 11.62%. Sensory evaluation indicated that the samples were highly rated (P<0.05) for all the parameters investigated. Sample E (50% millet, 20% soybean and 30% African locust bean pulp flour) was most acceptable to the panelists and should be encouraged in weaning food preparation. Key words: African locust bean fruit pulp, complementary foods, functional oroperties, chemical composition.

A comparative study on stability of different types of coconut (Cocos nucifera) oil against autoxidation and photo-oxidation

Abstract: This study aimed to compare the stability of five types of coconut (Cocos nucifera) oil available in Sri Lanka. The types of coconut oil studied were coconut pairing oil (CPO), white coconut oil (WCO), refined bleached and deodorized coconut oil (RBDCO), virgin coconut oil (VCO) and coconut oil (CO). Oils were exposed to elevated temperature (60±5°C) in the presence of excess air or oxygen to induce autoxidation and florescent light (2650 lux) to induce photo-oxidation in 28 days of storage. Samples were taken on 0, 1, 3, 5, 7, 14, 21 and 28 days to assess the level of oxidation by peroxide value (PV), conjugated dienes (CD), conjugated trienes (CT) and thiobarbituric acid reactive substances (TBARS) with time. WCO and VCO possessed the highest oxidative stability against autoxidation followed by CO and CPO, while, RBDCO showed the lowest stability. WCO and VCO possessed highest stability against photo-oxidation. CO was more susceptible to photo-oxidation among the oils examined followed by CPO and RBDCO. WCO and VCO possessed similar stability against both autoxidation and photo-oxidation. VCO has highest monounsaturated fatty acid: polyunsaturated fatty acid ratio (4.28) and suitable n6/n3 ratio (5:1); hence applicable as whole purpose oil which is resistant to processing and storage conditions with good nutritive value. Key words: Autoxidation, coconut oil, fluorescent, oxidative stability, photo-oxidation.

Quality of porridge from sub-Saharan Africa evaluated using instrumental techniques and descriptive sensory lexicon - Part 1: Thick (stiff) porridge

Abstract: The sensory attributes of thick porridges made from different composite flours in neutral, citric acid or sodium bicarbonate media was identified using instrumental methods and modified quantitative descriptive analysis. The results showed that composite flours with high cassava concentrations had lower pasting temperatures but higher peak, breakdown, final and setback viscosities than the cereal-rich flours. The onset pasting temperatures of alkali-treated slurries were higher (p < 0.05) than for the neutral- or acid-treated slurries. Acid-treated slurries had higher (p < 0.05) peak viscosities than neutral- or alkali-treated slurries. Acid-treated slurries had higher (p < 0.05) breakdown viscosities as compared to the neutral slurries. The toughness and work of shear of thick porridge ranged between 0.21 - 0.58 kg and 0.83 - 5.95 kg·mm, respectively. Thick porridge cooked in alkaline media was significantly darker (p < 0.05) than that made in neutral or acid media. Principal component analysis identified four major principal components (PCs) that accounted for 87.6% of the total variance in the sensory attribute data. The principal component scores indicated that the location of each porridge along each of the four scales corresponded with attributes associated with sodium bicarbonate aroma and taste (PC1); cassava aroma and hardness (PC2); colour of thick porridge (PC3); and finger millet/sorghum aroma (PC4). Thick porridges targeting specific consumer groups in sub-Saharan Africa can be developed by appropriate choice of flours and pH thereby forming the basis for commercial production of thick porridges for different population categories in sub-Saharan Africa with diverse sensory expectations of the product. Key words: Colour, texture, thick porridge, quantitative descriptive analysis.

Nutritional and sensory evaluation of African breadfruit-corn yoghurt

Abstract: Single extracts of African breadfruit (Treculia africana var africana) and sweet corn (Golden cob F1) were blended on 60:40 proportions to produce breadfruit-corn milk. The breadfruit-corn milk was fermented to obtain a yoghurt-like product (breadfruit-corn yoghurt), using inoculums drawn from activation batch of dried starter and previously made breadfruit-corn milk. The breadfruit-corn yoghurt was subjected to nutritional and sensorial evaluation using commercial cow milk yoghurt as a control. The breadfruit-corn yoghurt was significantly (p<0.05) higher in moisture, carbohydrate, calcium, potassium, magnesium, iron, zinc, vitamin B2 and vitamin C. The commercial cow milk yoghurt was significantly (p<0.05) higher in protein, fat, ash, crude fibre, sodium, manganese, vitamins A, B1 and B3. Sensory scores show that the commercial milk yoghurt was significantly (p<0.05) higher in all the sensory attributes considered. In all, the breadfruit-corn yoghurt has acceptable nutritional and sensorial qualities which show it is a potential alternative to cow milk yoghurt from economic and health perspectives. Key words: Yoghurt, lactic acid bacteria, nutritional, fermentation, breadfruit-corn yoghurt.

Proximate composition, physical characteristics and mineral content of fruit, pulp and seeds of Parinari curatellifolia (Maula) from Central Malawi

Abstract: In this study, proximate composition, physical characteristics and mineral content of fruit, pulp and seeds of Parinari curatellifolia (Maula) fruits from Bunda forests in Central Malawi were determined. Proximate composition included crude protein, crude fat and crude fiber, while physical characteristics included mass, length, thickness of whole fruit and kernels and minerals included potassium, magnesium, manganese, copper, zinc, iron and phosphorus. Total carbohydrate contents were also determined. All the results have been presented on dry matter basis. Results on crude protein ranged from 3.9±0.03 to 15.61±0.05% with pulp registering the lowest values (P<0.05) while the highest values were registered in kernels. Results on crude fat revealed that kernels had the highest values (46.05±0.19%) compared to values obtained in pulp or a mixture of pulp and peels while for crude fiber, the highest values (21.39±0.28%) were obtained in whole fruit. Furthermore, results on ash content showed that the highest values (5.71±0.25 %) were obtained in fruit peels while the lowest values (1.58±0.15 %) were registered in whole fruit. Lastly, results on carbohydrate content revealed that the highest values (84.95±0.14%) were obtained in the pulp while the lowest values (34.34±0.21%) were registered in kernels. The findings from this study have shown that there are significant differences in nutrient and mineral composition in the whole fruit, seeds and pulp of P. curatellifolia from Central Malawi and therefore these findings can be useful in nutritional planning regarding consumption of the P. curatellifolia fruit. Key words: Maula (Parinari curatellifolia), indigenous fruits, kernels, minerals, crude protein, nutrition, Bunda forest.

Isolation and identification of probiotic Lactobacillus species from traditional drink kunun-zaki fortified with paddy rice and sweet potatoes.

Abstract: The present study was conducted to determine the probiotic properties of the lactic acid bacteria (LAB) isolated from Kunun-zaki processed with different thickeners. Kunun-zaki was processed using 50:50 and 80:20 millet and sorghum. A total of seven isolates that is, Lactobacillus (Lb.) lactis, Lactobacillus casei, Lactobacillus brevis, Lb. acidophilus, Lactobacillus fermentum, Lactobacillus delbrueckii and Lactobacillus plantarum were isolated. The isolated LAB showed good growth in the presence of 1% NaCl but none at 10% NaCl except L. plantarum. The susceptibility of isolated Lactobacillus toward selected pathogenic organisms was determined using standard agar well diffusion method. Lb. plantarum was predominant and showed the most significant antimicrobial inhibition against tested pathogenic strains (Pseudomonas aeruginosa, Staphylococcus haemolyticus and Klebsiella pneumoniae) tested followed by Lb. casei. The results of this study showed that LAB species isolated from Kunun-zaki processed fulfill the most common criteria of probiotic bacteria. Therefore, numerous probiotic products can be developed from Kunun-zaki. Key words: Probiotics, kunun-zaki, Lactobacillus spp., antimicrobial inhibition.

Two withanolides from Withania somnifera (solanaceae) and activity of methanolic extracts against fungal and bacterial pathogens that affects food crops

Abstract: Methanolic extract obtained from the dried leaves of Withania Somnifera was subjected to column chromatography leading to the isolation of two withanolides. Their structures were elucidated using 1D and 2D NMR spectroscopy. The isolated withanolides were determined to be 5α, 17β-dihydroxy-6α, 7β-epoxy-1-oxo-witha-2, 24-dienolide (1) and 4, 5, 6, 15-tetrahydroxy-1-oxo-witha-7-enolide (2). The bioassay of the methanolic extracts showed activity against the fungal pathogens, Fusarium moniliforme, Fusarium graminearum, Colletotrichum lindemuthianum and Pythium spp. The extract was also active against bacterial pathogens, Xanthomonas campestris pv. phaseoli and Pseudomonas syringae pv. phaseolicola. The withanolides did not show any bioactivity indicating that they are either active only synergistically with other compounds within the extracts or there are other active compounds in the extract. Key words: Withania somnifera, withanolides, methanolic extract, antifungal, antibacterial.

Preparation and analysis of goat milk mozzarella cheese containing soluble fiber from Acacia senegal var. kerensis

Abstract: Mozzarella cheese is one of the preferred ingredients for use in pizza. Goat milk is a good source of protein and calcium, possessing unique characteristics with a high proportion of small milk fat globules that contain a higher concentration of short chain, medium chain and polyunsaturated fatty acids than cow’s milk. Its use in mozzarella cheese can therefore impart significant health benefits to consumers. However, despite these unique qualities, goat milk is underutilized in Kenya. Gum arabic is an excellent source of soluble dietary fiber, which can be used to boost fiber levels in cheese and other dairy products. Thus, the aim of this study was to investigate the feasibility of incorporating gum arabic as a source of fiber in goat mozzarella cheese without affecting the functionality of the cheese. Gum arabic powder at 2, 3 and 4% was incorporated into cheese during the salting process at room temperature (20 to 25°C). The functional properties of the cheese: stretchability, free oil formation and meltability were then determined. Sensory evaluation was conducted using 50 untrained sensory panelists on a 5-point hedonic scale. The results indicated that the use of gum arabic in mozzarella cheese up to a level of 3% improved the stretchability and meltability while reducing the free oil formation phenomenon. Texture, flavor, color and overall acceptability were also rated as best for samples containing gum arabic at a level of 3%. The results showed that the use of gum arabic can improve the functional properties, nutritional quality as well as sensory quality of goat milk mozzarella cheese. Key words: Gum arabic, dietary fiber, mozzarella cheese, goat milk, functional properties.

The effect of mechanical kneading and absit preparation on tef injera quality

Abstract: The aim of this study was to investigate the effect of mechanical kneading and ‘absit’ preparation difference on the quality of tef injera, the staple food of Ethiopians. Standard methods were adopted to determine the starch fraction, total phenol, flavonoid, phytate and tannins of injera. Sensory injera quality was assessed using 9-point-hedonic scale. Change in kneading conditions (time/speed) did not significantly affect the free sugar (FSG), slowly digestible starch (SDS), resistant starch (RS), total starch(TS) and starch digestion rate index (SDRI). On the other hand, significant variation was observed in rapidly available glucose and rapidly digestible starch (RAG and RDS). Flavonoids, total phenolics and phytate contents varied significantly at different kneading time- speed combinations. Injera sensory quality was also significantly affected due to change in kneading conditions. Kneading condition 5 (3 min at speed 6) has the highest injera overall acceptability while kneading condition 9 (7 min at speed 12) had the lowest. In addition to kneading conditions, absit preparation (water to fermented dough ratio) was also found to affect the quality of tefinjera. Absit # 3 made from 100 ml of fermented dough and 900 ml of water had the highest injera overall acceptability while, the lowest was observed on Absit # 4 made from 300 ml of fermented dough and 100 ml of water. In conclusion, both kneading and absit preparation significantly influenced starch hydrolysis, flavonoids, total phenolics and phytate contents as well as sensory quality of injera. Key words: Kneading, sensory quality, absit preparation, starch fractions.

Physicochemical, microbiological and sensory characteristics of cashew milk formulated yoghurt

Abstract: Cashew yoghurt was formulated using cashew kernel milk. The physicochemical, microbiological and organoleptic assessment of the resulting product was examined and compared with commercial yoghurts. Results indicated that crude protein of 16.8% for cashew milk yoghurt compared favorably with 14.82% of commercial yoghurt. Caloric value of cashew yoghurt (133.06 kJ) was higher than that obtained for commercial yoghurts (112.01 kJ). Microbiological study revealed a total count of 1x106 CFU/g, which was attributed to the culture used in the fermentation process. The cashew milk yoghurt was generally accepted by the panelist as there were no differences in the sensory characteristics examined; however, there was a difference at p> 0.05 for mouth feel for the sample studied. It can be concluded that cashew milk serves as a potential recipe for acceptable yoghurt formulation. Key words: Cashew kernel, yoghurt, sensory, protein, organoleptic.

Pasting, morphological and functional properties of breadfruit (Artocarpus altilis) starch crosslinked with ethylene glycol dimethacrylate

Abstract: A novel succinylated crosslinked starch was prepared by using ethylene glycol dimethacrylate (EGDMA) as a crosslinker. In this current research, the study was designed to investigate the influence of single and dual chemical modifications on functional, pasting and morphological properties of starch extracted from breadfruit. The extracted starch was chemically modified to produce succinylated (SST) and succinylated-crosslinked starches (SCT). Proximate analysis revealed that following modifications, SST starches retained higher moisture content compared to native starch, while SCT starch had lower moisture content. Crude protein, crude fibre, crude fat and total ash of the native starch reduced following succinylation but increased after crosslinking. Scanning electron microscopy (SEM) revealed that crosslinked granules were not uniformly distributed but formed some aggregates.The absorption bands of the carbonyl group at 1784 and 1716 cm-1.appeared in FTIR spectra.The result indicates that all forms of modificationreduced the water binding capacity of native breadfruit starch. Gelation studies revealed that crosslinked breadfruit starch had a superior gelating property than the succinylated and native starches. The values of 94.70 and 79.95 OC obtained for the pasting temperature of SST and SCT respectively were higher than corresponding value of 79.90 OC listed for native starch. All forms of modification reduced peak viscosity, trough viscosity, breakdown viscosity and final viscosity of the native starch. Setback viscosity reduced after succinylation but increased in crosslinked derivative, indicating less syneresis is likely to take placewithin the starch helices.

Food insecurity in the green famine belt of Ethiopia: Extent and severity in Belo-jiganfoy District, Benishangul-gumuz region

Abstract: The green famine belt of Ethiopia is customarily viewed as food secure area only due to relatively adequate rainfall and green vegetation cover. In contrast, this paper argues and shows that the food insecurity condition termed as “green famine” has always existed in the belt. Accordingly, the paper examined the extent and severity of food insecurity based on a cross-sectional survey of 220 households in Belo-jiganfoy district. A structured questionnaire was employed to collect data. A household food balance model was used to determine the food insecurity status and then to compute the head count ratio and food shortfalls index for determining the extent and severity of food insecurity respectively. The result showed that food insecurity was widespread and deep-rooted. The head count ratio showed that about 72% of the surveyed households were food insecure. The food shortfall index showed that on average households were 48% far below the food security threshold. The household food insecurity access prevalence showed that about 62% of the respondents were food insecure at different levels of severity: 21% mildly, 23% moderately, and 18% severely food insecure. Small-scale irrigation, wage labor, family size, land size, livestock, off-farm income and household head education were significant determinants of food insecurity. Therefore, it is safe to conclude that the extent and severity of food insecurity in the green famine belt is at best similar with, and at worst more than, the situation in the drought-prone and non-green famine areas of Ethiopia. Key words: Food insecurity, extent, severity, determinants, Western Ethiopia.

Microbiology, heterocyclic amines and polycyclic aromatic hydrocarbons profiles of some grilled, roasted and smoked foods in Lagos and Ogun States, Nigeria

Abstract: Dietary intake of polycyclic aromatic hydrocarbons (PAH) and heterocyclic amines (HCA) has posted a great health risk as they have been identified as a most potent human carcinogen. Microbial quality of food is also of concern as they contribute to food poisoning and infection. Sixty food samples comprising roasted yam, plantain, grilled and smoked fish and meat were randomly sampled from Lagos and Ogun State, Nigeria, and the PAHs, HCAs contents and microbial load were determined. Isolates were subjected to antibiogram assay. The pH of the samples ranged between 5.08 and 7.49, titrable acidity was in the range of 0.50 and 1.20. Staphylococcus, Bacillus, Micrococcus, Proteus, Pseudomonas, Citrobacter and Klebsiella sp. had been identified. Antibiogram revealed that the isolates were multi-resistant and most resistant to ceftazidime, cloxacillin and tetracycline and more susceptible to ofloxacin. PAHs were detected in some grilled, roasted and smoked samples and with the highest concentrations 314.85 and 139.97 μg/g Dibenzene[a,h]anthracene established in roasted yam and smoked fish samples. Only 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was detected in grilled fish and meat samples. This study therefore established the presence of chemical and microbial contaminants in some of the food items investigated. It recommended that strict sanitary practices and appropriate cooking methods be enforced during food preparation.

Weaning food fortification and improvement of fermented cereal and legume by metabolic activities of probiotics Lactobacillus plantarum

Abstract: The provision of cheap, balanced and adequate nutritional composition for growing infants is a major challenge in Africa. Most weaning foods are usually cereal-based gruels fermented by lactic acid bacteria (LAB). The major nutrient they supply being carbohydrate, uncontrolled or inappropriate intake might cause growth retardation and malnutrition in growing children. The nutritional requirement of weaning infants could be supplied by supplementation with protein rich diets. Soybean is a cheap and available source of protein in Nigeria; but it also contain some complex sugars (raffinose) which is associated with abdominal discomfort in children of weaning age. This study is designed to use the probiotics LAB to improve the nutritional composition of weaning food blends. Lactic acid bacteria were isolated from Ogi (a fermented cereal gruel) using standard morphological and biochemical tests; their identities were confirmed with molecular methods. Nutritional and organoleptic attributes of the food blend were determined following Association of Official Analytical Chemist procedures. The data were subjected to statistical analysis at 5% level of significance. Fortification of the gruel with pre-treated soybeans improved the nutritional quality (Protein: 8.4 to 17.8 %; Fat: 3.6 to 12.9 %; Ash: 2.0 to 3.8%; Fe: 6.4 to 10.7mg/100g and Ca: 156.7 to 211.0mg/100g) during fermentation. Utilization of raffinose by probiotic Lactobacillus plantarum from local food sources reduced the complex sugars in soybeans. Nutritional qualities and organoleptic attributes of cereal gruels were improved by fortification with soybeans and fermentation. Key words: Probiotics, complex sugars, Lactobacillus plantarum, fermentation, nutritional improvement, soybeans.

Effect of pretreatments on the microbial and sensory quality of weaning food produced from blends of sorghum and soybean

Abstract: This study investigated the effect of pre-treatment on the microbial and sensory quality of weaning foods produced from blends of sorghum and soybean. Sorghum and soybean were fermented, roasted and fermented/roasted, then milled into flours. Untreated sorghum and soybean flours were also produced separately and serve as the control. A portion of sorghum was malted and milled to obtain malted sorghum flour of which 5% was added to each sample except the control samples. Weaning foods were prepared in the following ratios: (75:20:5), (65:30:5) and (55:40:5) of sorghum: soybean: malt for the treated samples and the control samples contained (80:20), (70:30) and (60:40) of untreated sorghum : soybean. The microbial and sensory qualities of the samples were determined. The result of the microbial analysis of the formulated weaning food blends showed that all samples indicated a safety for consumption. The appearance of both treated and untreated were not significantly different (p<0.05) while the means scores of the blends in texture, taste, aroma and overall acceptability were significantly different (p<0.05). Fermentation and roasting used in this study showed that the processing methods had marked effect on the microbial and sensory quality of the weaning foods produced, thus, its recommendation for domestic processing of weaning foods. Key words: Pretreatments, weaning food, sorghum, soybean, microbial and sensory qualities.

Enhancement of eritadenine production using three carbon sources, immobilization and surfactants in submerged culture with shiitake mushroom (Lentinula edodes) (Berk.) Singer)

Abstract: In this study, the effect of three carbon sources (mannitol, minced potato and sucrose), two immobilization substrates (alginate and wood cylinders), and three surfactants (Tween 20, Tween 40 and Tween 80), were evaluated on eritadenine production using shiitake (Lentinula edodes) mycelium under submerged cultivation, in shake flasks within 20 days. Eritadenine and biomass were measured by HPLC and gravimetrically, respectively. Alginate immobilization of mycelium promoted significant enhancement of eritadenine yields of 88 mg/L, compared to the control (8.7 mg/L) and wood immobilization (14.8 mg/L). Likewise, eritadenine yields (72.4 mg/L) were enhanced by adding surfactant tween 20 to the broths in 0.5%, than control (8.7 mg/L) without surfactant. Tween 40 and 80 did not improve eritadenine yields, but both produced better biomass values (superior to 5 g/L) than the control (3.9 g/L). All carbon sources (sucrose, mannitol, mince potato, and glucose as control) produced similar low eritadenine yields, with best results (10.2 mg/L) by sucrose, although glucose produced the best biomass yields of 3.9 g/L. Also, carbon sources and the best biomass values did not show significant effect on eritadenine production. pH values in the best eritadenine yielding fermentations went down from 6 to 3-4, but pH had a low correlation with eritadenine yields. Finally, all data obtained in the present study are useful for optimizing culture conditions, towards industrialization of this important health improver metabolite (eritadenine). Key words: Eritadenine, shiitake mushroom, submerged culture, immobilization, surfactants.

Effects of germination and defatting of the soybean and sesame on the mineral bioavailability and absorption of sweet potato based complementary diets

Abstract: The effect of germination of soybean and sesame seeds on the bioavailability of minerals of complementary foods was investigated using rats. Formulations of complementary diets 1 to 4 were produced from sweet potato, soybean and sesame flours at a ratio of 60:30:10, respectively. Formulated diets were significantly higher (p<0.05) in protein, fat and moisture content and lower in carbohydrate and crude fibre than in control. Diet 4 was significantly higher (p<0.05) in minerals (Ca, Zn and Fe) content than in control. The formulated diets were generally low in phytate and oxalate contents, while phytate content was much lower in the diets from germinated flour blends. Anti-nutritional factor (ANF): mineral molar ratio suggested good mineral absorption from the formulated diets. Mineral content of the tissues of rats fed with the formulated diets indicated good absorption within the rats; rats fed with the germinated flour blends had significantly higher (p<0.05) zinc, iron and calcium contents of tissues when compared. Diet 4 consistently received better rating among the samples. Key words: Complementary food, sweet-potato, germination, anti-nutrient, micronutrient.

Sensory evaluation and consumer acceptability of orange-fleshed sweet potato by lactating women and their children (

Abstract: This study evaluated the sensory properties and consumer acceptance of boiled, fried, and mashed orange-fleshed sweet potato (OFSP), by rural lactating women (n=80) and their children <2 years old (n=77). Sensory evaluation and acceptability were performed using a 7-point hedonic scale. Intake parameters (food intake and eating rate), and vitamin A content in the OFSP were measured. The relationships between the sensory descriptors and the type of OFSP preparations was analysed using principal component analysis (PCA) plot. Frying and boiling the OFSP decreased the vitamin A content by 50%, but an acceptable level of retinol was maintained. For all sensory attributes, mothers preferred fried OFSP over boiled, while their children gave high acceptability scores to both boiled and mashed OFSP. The success of the OFSP cultivar, which is newly introduced in Kaffrine, and its high acceptability are promising for the prevention of maternal and child vitamin A deficiency in the rural areas of Senegal. Key words: Orange-fleshed sweet potato, sensory evaluation, consumer acceptance, Senegal.

Meat quality analysis of Djallonke lambs co-infected with Teladorsagia circumcincta and Trichostrongylus colubrifromis (Trichostrongyloidae) and treated with two medicinal plants

Abstract: Gastrointestinal nematode infection adversely affects small ruminant productivity all over the world, especially in tropical countries. A study was carried out to evaluate the extent to which concurrent infection with these nematodes may influence lamb meat quality, and how phytotherapy might improve these parameters. During the trial, 24 male Djallonke lambs (Age: 3 to 5 months) were experimentally infected with Teladorsagia circumcincta (4000 infective larvae) and Trichostromgylus colubriformis (10000 infective larvae) and treated from day 26 post infection with methanol extracts of Harungana madagascariensis and Momordica foetida twice daily. Lambs were divided into 8 groups: An untreated (Group 1), Albendazole 7.5 mg/kg (Group 2), H. madagascariensis extract at 125 mg/kg (Group 3), H. madagascariensis extract at 250 mg/kg (Group 4), H. madagascariensis at 500 mg/kg (Group 5), M. foetida extract at 125 mg/kg (Group 6), M. foetida 250 mg/kg (Group 7), and M. foetida at 500 mg/kg (Group 8). Meat quality attributes of lambs from different treatment groups were evaluated. Treatment with different doses of plant extracts led to differences in the level of parasitic load at necropsy. This effect was accompanied by an elevated pH24 in meat from the most severely infected lambs and a concomitant decrease in their chemical composition. This high pH24 equally had significant influence on meat flavour, overall acceptability and water retention of lamb meat. The present study suggested that nematode infection may influence pH of resulting carcass, nutritional composition and some sensory parameters of meat while treatment using M. foetida at 500 mg/kg maybe important in reducing parasite burden while enhancing quality of subsequent lamb carcass. Key words: Phytotherapy, meat quality, Teladorsagia circumcincta, Trichostrongylus colubriformis, Harungana madagascareinsis, Momordica foetida, Djallonke lambs.

Thermoprocessment of tambaqui fish in tucupi sauce

Abstract: Canning of juvenile tambaqui (Colossoma macropomum) was carried out using \"tucupi\" cover dressing (regional sauce) and the acceptability of the preserve was tested. Cans were thermally processed at 121°C for 20 mins, 25 mins and 30 mins. The \"in natura\" centesimal composition and the products were determined according to A.O.A.C, commercial sterility and microbiological quality was verified and the Kruskal-Wallis ANOVA was used to evaluate the results of the study. Cans with heat treatment of 121°C for 30 mins showed better bone decalcification and its centesimal composition was 71.29% of humidity; 20.98% protein; 5.87% lipids; 1.75% ash and TCV (Total Caloric Value) of 138 Kcal EB.100 g-1. All canned tambaqui fish had an acceptance index above 95% and intention to buy above 5 (would eat frequently). The \"tucupi\" sauce was approved by 100% of the evaluators and its use for canning has the advantage of the great availability of the raw material (wild cassava), resulting in a low production cost and a new type of product offering to the consumers.