Influence of processing methods on the quality attributes of bio-fortified sweet potato products

Bio-fortified sweet potato (BSP) is one of the crops that can be used to address the problems of vitamin A deficiency in the Sub-Saharan Africa but it’s currently being underutilized. This study seeks to evaluate the effects of different heat processing methods on the quality of products made from BSP in order to increase its utilization. Freshly harvested tubers were purchased from a Research Farm in Federal University of Agriculture, Abeokuta (FUNAAB), Nigeria and brought to the Processing Centre, Nigerian Stored Products Research Institute (NSPRI), Ilorin. The sample was taken through some standard pre-processing operations of sorting, peeling, washing, slicing (2.11 mm), and deep frying (3 minutes) while some portions were boiled immediately after sorting with or without skin for 10–15 minutes. Each treated sample was analysed for sensory, proximate, vitamins and mineral compositions following standard methods. Results showed that fried sample had highest acceptability for aroma (7.25) and crispiness (7.00) while sample boiled without skin (15 min) was rated with least scores in colour (5.30), appearance (5.40), texture (4.95), crispiness (4.65) and overall acceptability (5.70). Protein, vitamin C, phenolics, flavonoids and reducing sugar contents were 6.53–18.52%, 10.89–76.69 mg/100 g, 0.57–3.15 mg/L, 94.64–383.91 mg/L and 43.05–237.12 g/100 g respectively while some minerals such as Na, K and Zn ranged from 8.42–17.45, 5.12–9.30 and 0.03–0.09 mg/L respectively. Different heat processing at different durations affected the sensory attributes, nutritional and mineral compositions of BSP. Key words: Post-harvest, food security, potato, heat treatment, qualit

Post-Harvest Challenges of Marketers of Selected Neglected Crops in South-East and South-South, Nigeria

Research works on neglected crops have been based on production improvement with little or no attention on other key value chains such as marketing. This study examined the challenges of marketers of selected neglected food crops (Bambara nut: Vigna subterranean; Breadfruit: Artocarpus altilis and Bush-mango: Irvingia gabonensis) in Southern Nigeria. A multistage random sampling technique was used to select 144 respondents from 6 major markets and structured questionnaire administered, while descriptive analysis was used to analyze the data. The results revealed the mean age of the marketers as 40 years, 86.8% females and 83.3% literate. The mean number of house-holds was seven (7) persons and marketing experience of 10.1 years. The average quantities of purchase for each crop were 5131.1250kg (Bambara nut), 77.4288kg (Breadfruit) and 246.7600kg (Bush-mango). The average lengths of storage of these crops before selling were 102, 30 and 77days for Bambara nuts, Breadfruits and Bush-mango respectively. Causes of losses were attributed to the following; 27.7% insect and pest, 42.4% mold, and 29.9% rodents. About 2.8% of the neglected crop marketers used sniper for the preservation of their crops, while 27.8% out of the other 97.2% used bio-insecticide.  Constraints militating against the sale of these neglected food crops in the study area were; lack of organized market, lack of financial support, high cost of transportation, strenuous market purchase, and susceptibility to pests, and lack of storage facility. The study therefore, recommends that marketers be encouraged to form or belong to trade associations or cooperative societies to enhance access to loan, and research into Post-harvest technology related to the selected food crops (such as storage structures and processing equipment) should be developed and disseminated appropriately

Attractancy of diethylether and hexane extracts of maize (Zea Mays L.) to Oryzaephilus mercator (fauve1) (Coleoptera: Silvanidae)

Diethylether and hexane extracts of maize attracted 1-7 and 28-42 day-old  Oryzaephilus mercator adults. The 1-7 day-old adults were significantly more responsive than the 28- 42 day-old. Starvation of adults for up to 3 days progressively increased O. mercator response. Hexane extracts were more attractive than  diethylether extracts. Within the extract concentration range of 0.02, 0.04, 0.06, 0.08, and 1.0ml, optimal response of O. mercator occurred at 0.06m1 and beyond this level, negative response was observed. There were significant interactions between age and solvent; age and starvation period; solvent and extract concentration; age and extract concentration; starvation period and extract concentration, and among age, solvent, and starvation period; age, solvent, and extract concentration; and solvent, starvation period, and extract concentration. Probable reasons for the results obtained are  discussed

Effect of different processing methods on the meat of Tympanotonus fuscatus

50kg periwinkle was purchased from Oyingbo market in Lagos State, South-west of Nigeria. The bag contained a mixture of two species namely; Tympanotonus fuscatus var fuscatus and Tympanotonus fuscatus var radula. They were processed to remove the meat from the shell. The fresh periwinkle meats were dried in the multipurpose produce dryer designed by Nigerian Stored Product Research Institute’s (NSPRI) for 15hrs at a temperature of 60oC (Sample A). Fresh and dry periwinkle meats were bought from Iddo Market in Lagos to serve as control (Sample B). The moisture contents of fresh and dry Sample A were 81.20% and 6.52% respectively while that of fresh and dry Sample B were 79.60% and 10.45%. Also, the results of microbial analysis of fresh and dry periwinkle (Sample A) showed sample count of 5.8cfu/g and1.2x10-1cfu/g respectively. No pathogenic organisms (E.coli, Salmonella spp.) and fungi were isolated. The microbial analysis carried out on Sample B showed high microbial load (Fresh: 6×103cfu/g, Dry: 1.2×103cfu/g). Statistical analysis revealed a significant difference (p< 0.05) for microbial loads in both fresh and dried samples between Samples A and B while there was no  significant difference in the moisture contents of the two samples. Ten per cent (10%) of foreign matters was found in sample B; it also appeared brownish and rough with a repulsive odour. The heavy metals analysis for sample A and B revealed that the amounts present were all within safe limits except for copper at  35.61mg/kg-1 in sample B. This is against its safe limit of 1.20 mg/kg-1 recommended by European Union (EU) standards on fish and other sea foods. Based on the findings from this research work, members of the public should be educated on the importance of proper processing methods on the quality of periwinkle meat.Key words: periwinkle, processing, nutritive value, heavy metals, dry

Survey of aflatoxins contamination in selected agricultural commodities obtained from major markets in six geographical zones in Nigeria

This study evaluated total aflatoxin contents of six agricultural commodities obtained from major markets in six geographical zones of Nigeria. Results showed that total aflatoxin levels in cowpea, yam chips and dried fish from six zones were less than European Union (EU) recommended maximum safe level (4 ppb) while 16.67% of groundnut samples and 83.33% each of melon and maize had total aflatoxin above 4 ppb. Moisture content of groundnut, melon, dried fish, yam chips, cowpea and maize significantly ranged from 3.92–7.74%, 3.15–5.73%, 7.76–14.39%, 9.66–17.04%, 7.84–10.94% and 10.13–13.31% respectively. Insect infestations of food commodities were light and most of the few insects found were dead. Thus cowpea, dried fish and yam chips from six zones with maize and melon from N. West zone of Nigeria could be regarded as being free from aflatoxins contaminations. It was also demonstrated that proper postharvest handling and adherence to simple good agricultural practice (GAP) were enough to improve the quality of produce internationally. Food commodities from Southern zones had significant (p<0.05) higher moisture than those from the Northern zones. Keywords: Nigeria, mycotoxins, hazards, safety, food, feed

Comparative assessment of quality of tilapia (Oreochromis niloticus) and catfish (Clarias gariepinus) stored in ice fish box

The quality of two species of fish, (Tilapia) Oreochromis niloticus and (Catfish) Clarias gariepinus stored in the Ice fish box was assessed with fish to ice (1:1, 2:1, 3:1 and 4:1) for 36 and 30 hours respectively. The parameters assessed were: PH, Rigor Index, TVB-N, Sensory Evaluation, Temperature, Relative Humidity and Microbial Analysis. The lowest average temperature and relative humidity for all the treatments were 5.70C and 87.7%, and 5.20C and 93.3% for Tilapia and Catfish respectively. Biochemical analysis revealed pH value for Tilapia decreased significantly (p<0.05) within the storage period for all the treatments. From an initial value of 6.90 to between 6.50-6.80 at the end of storage period (36 hours), for Catfish there was a significant difference (p<0.05) from an initial of 7.1 to 7.6. This increase was steady across all treatment at the end of the storage period (30 hours). The TVB-N value for Tilapia increased significantly within the storage period for all the treatments from an initial value of 5.29mg to 7.22mg, 8.82mg, 12.10mg and 13.28mg respectively for 1:1, 1:2, 1:3, 1:4. Similar trend was reported for catfish from an initial value of 0.98mg to 16.56mg. These values were significantly different (p<0.05).The microbial load did not increase significantly for all the treatment within the storage period. Total Viable Count (TVC) ranged from an initial of 1x102 to 3x102 cfu/g and an initial of 1x102 to 4x102 cfu/g for Tilapia and Catfish respectively. The sensory assessment and organoleptic evaluation of both species were satisfactory at the end of the storage period. However, overall assessment indicates that Tilapia stored longer in the Ice fish box than the Catfish.Keywords: Organoleptic assessment, Storage, Quality, Fish, Ic

Chemical and physico-chemical properties of orange fleshed sweet potatoes (OFSP) chips dried using solar dyers

In this study, drying technology was employed to process fresh orange fleshed sweet potatoes (OFSP) into dried slices using NSPRI improved solar tent dryer, parabolic shaped solar tent dryer in comparison with open air drying and its effect on the chemical, physico-chemical and mineral constituents of dried OFSP slices was investigated. Results showed that the dried-OFSP contained ash (3.69-4.09 %), fat (4.09-5.09 %), crude fibre (4.69-5.15 %), protein (5.87-8.28 %), carbohydrate (78.22-82.21 %), vitamin C (8.55-20.49 mg/100g), phenolics (0.1-1.28 mg/kg), flavonoids (984-145 mg/kg) and reducing sugar (35.01-82.23 g/100g). The total titratable acidity of the dried OFSP slices varied between 0.56-0.89 %, total soluble solids ranged between 5.70-7.00 °Brix while pH ranged between 4.94-6.47. Zinc, magnesium, potassium, calcium, sodium, iron were present in varying levels but aluminium, lead and cadmium were not detected in all the samples. This study therefore showed that good quality dried OFSP slices with appreciable nutrient content can be obtained from drying in NSPRI solar tent dryers especially with the use of the parabolic shaped solar tent dryer. Thus, the parabolic solar tent dryer is recommended for drying crops. Keywords: Drying technology, Orange fleshed sweet potato, NSPRI solar dyers, Physicochemical propertie