Food Science

Five green leafy vegetables (Basella alba, Vernonia amygdalina, Talinum triangulare, Manihot esculenta and Corchorus olitorius) were analysed for their moisture, crude protein and ascorbic acid contents. The vegetables were earlier differently sun-dried, stored in the refrigerator and stored in the freezer for five days each before the ascorbic acid contents were determined. Moisture and crude protein were high in all the samples. The between the sample variations in the ascorbic acid contents were high in the fresh (zero day) with values ranging from 234 mg/100 g (recorded in T. triangulare and C. olitorius) to 1041.3 mg/100 in g V. amygdalina. The highest between the day variations in the values of each sample were recorded in the samples kept in the freezer (45.7 % -131.3 %) but lowest in the sun-dried samples (23.6 %-75.7 %); the rate of value change per sample per day also followed this observed trend. The ascorbic acid values in the sun-dried samples were significantly different at p ? 0.05. The percentage loss of ascorbic acid contents in the five days was found to be sample as well as storage condition dependent.

We assessed the hypoglycemic, hypolipidemic as well as the antioxidant potential effects of the Opuntia streptacantha cladodes juice (OSCJ) in alloxan-induced diabetic rats (140 mg/kg of body weight (bw)). The results evidenced that alloxan-induced diabete, caused weight loss, polyphagia, hyperglycemia, hyperlipidemia and the disturbance of enzymatic and non-enzymatic antioxidant systems. The daily oral administration of OSCJ (30 g/kg of b.w during 4 weeks) to diabetic rats clearly improved the antioxidant status in liver and kidney. Such fact is materialized by a decrease in the lipid peroxidation product, thiobarbituric acid-reacting substances (TBARS) level and an increase in glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) activities. Histopathological investigation of the pancreatic tissue of alloxan-diabetic rats indicated the presence of necrosis in the islets of Langerhans cells. The curative effect of OSCJ was well evidenced by normal islets of Langerhans cells, which explain its antidiabetic effect.

The occurrence of organochlorine pesticide residues in food matrices has become essential due to the toxicity and intransigence of these xenobiotics. Residue levels of organochlorine pesticides (OCPs) were determined in two leafy vegetables sampled from selected major growing areas in Ghana. The determination was carried out using Gas Chromatography/ Mass Spectrophotometer (GC/MS) procedures. The results indicated that cabbage samples had the widest spread of OCP contamination between the two leafy vegetables analyzed. Residues of pesticides (75%) were found in all samples obtained from Akuapem-Mampong compared to samples obtained from the Accra Metropolis (100%) indicating high occurrence of these xenobiotics in the vegetables collected from farms in Accra. The commonest organochlorine pesticides that were used by almost all farmers were endrin, p, p-DDE, p, p-DDD, p, p-DDT, ?-chlordane, endosulfan sulphate, ?-endosulphan, ?-endosulphan, ?-HCH, ?-HCH and lindane. The residual levels of OCPs in cabbage and lettuce clearly indicate that, samples obtained in the city had higher OCP levels compared to samples obtained from the rural areas. The study shows that application of pesticides at higher doses results in higher levels of the chemicals in vegetables thereby exposing the entire Ghanaian population and the consequent health implications. Regular monitoring of OCPs in vegetables and other food matrices is key to prevent their accumulation in the food chain.

Organochlorine pesticides (OCPs) were determined in twenty (20) pineapple and cocktail fruit juice of eight (8) brands collected from various markets in the Greater Accra Region, Ghana. Each brand was replicated thrice or twice based on diffrrent batch number. A survey was conducted to ascertain farmers view on organochlorine pesticides and pesticide/insecticide used during pineapple and mango production. Fruit juice samples were also analysed to investigate pesticide residue levels in them. Fruit juice samples were analysed by gas chromatography prepared with electron capture detector for organochlorines. Thirty (30) mango and twenty-five (25) pineapple farmers interviewed used pyrethroid based pesticides in controlling insect pest on their farm.Aldrin (0.007 ± 0.004 mg/kg), Dieldrin (0.001 ± 0.003 mg/kg), Endrin (0.0004 ± 0.001 mg/kg) cis heptachlor (0.000001 ± 0 mg/kg), Heptachlor (0.09 ± 0.088 mg/kg), trans heptachlor (0.0003 ± 0.001 mg/kg), trans_nonachlor (0.003 ± 0.004 mg/kg), alpha_HCH (0.002 ± 0.001 mg/kg), beta_HCH (0.000001 ± 0 mg/kg), delta_HCH (0.007 ± 0.008 mg/kg), gamma_HCH (0.003 ± 0.006 mg/kg), cis chlordane (0.000001±0 mg/kg), Hexachlorobenzene (0.0008 ± 0.001 mg/kg), o_p_DDD (0.00024 ± 0.001 mg/kg), p_p_DDD (0.005 ± 0.007 mg/kg) o_p_DDE (0.000001 ± 0 mg/kg), p_p_DDE (0.0006 ± 0.001 mg/kg), o_p_DDT (0.0009 ± 0.001 mg/kg), and p_p_DDT (0.0003 ± 0.001 mg/kg) were present in all the samples collected. The observations made on this studies, suggest that, effective regulations guiding the use of pesticides on fruits should be enforced and regular checks of pesticide residues in freshly consumed products.

The study was conducted to compare the nutritive values of Jatropha curcas seeds and kernels and the defatted products as well as to determine the correlation between the physical parameters of seeds/kernels and the chemical compositions. Jatropha seeds were collected from four different parts of Ghana where the plant is popularly grown (1. Nyankpala, Northern Region; 2. Wa, Upper West Region; 3. Dambai, Volta Region; and 4. Techiman, Brong Ahafo Region). The seeds were harvested in November, 2012 and the physical parameters of 1000 seed samples were determined. Jatropha seeds and kernels were also defatted to obtain seed and kernel meals respectively. The average whole seed and kernel weights were 0.69 ± 0.04 g and 0.43 ± 0.02 g respectively. The percentage kernel and shell of whole seed weight were in the ranges 61.19 - 62.74 % and 37.26 - 38.81 % respectively. The Kernels were significantly high (P < 0.05) in crude protein, CP (24.56 ±0.45 %) and lipid (56.14 ± 0.28 %) as compared to the whole seed CP (18.66 ± 0.11 %) and lipid (38.09 ± 0.29 %) respectively. The crude fibre was however significantly higher (P < 0.05) in the whole seed (15.70 ± 0.60 %) than the kernel (4.52 ± 0.26 %). The kernel weight had strong positive correlation with lipid value (correlation coefficient, r = 0.862) whereas shell weight showed strong negative correlation with CP and, lipid contents (r = - 0.857 and -0.759 respectively). More also, shell weight showed strong positive correlation with crude fibre content (r = 0.935). The J. curcas whole seeds contained significantly high (P < 0.05) amounts of antinutritional factors like crude phorbol ester (CPE), tannins and phytic acid as compared to the kernel. The J. curcas whole seed meal (WSM) and kernel meal (KM) varied in their nutritional compositions. The KM was very rich in crude protein, CP (64.04 ± 0.16 %) as compared to the WSM (28.60 ± 0.32 %). However, the crude fibre content was significantly low (P < 0.05) in the KM (6.79 ± 39 %) than the WSM (22.96 ± 51 %). The antinutritional factors were also higher in the WSM than the KM. The phytic acid value was significantly higher (P < 0.05) in WSM (9.45 %) than the KM (8.70 %). The CPE concentrations in both WSM (5.92 mg/g) and KM (5.55 mg/g) did not vary significantly (P > 0.05). The tannic acid concentration was however higher in the WSM (0.83 % tannic acid equivalent) while the value in the KM was negligibly lower (0.07 % tannic acid equivalent). The two Jatropha meal types (WSM and KM) contained considerable amounts of macro-minerals like phosphorus, potassium, calcium and magnesium. The correlations found between some physical parameters (kernel and shell weights) and nutritional characteristics of whole seed and kernels and their respective meal types (WSM and KM) show that some of these parameters could be used as indicators to predetermine both quality and process requirements for Jatropha seeds for use as animal feed.

Paprika oleoresin, obtained from capsicum species is used as a natural colourant and flavour enhancer in food and pharmaceuticals and is shown to be effective free radical scavengers including potential antioxidative and anticancer properties. The current investigation aims to evaluate the anticancer activity of developed MPO (Microencapsulated Paprika Oleoresin) on EAC tumour model. Male Swiss albino mice were divided into 6 groups (n=12). Group I (normal) animals received normal saline solution orally, all the other groups (Group II to VI) were injected with EAC cells (0.2 ml of 2 x106 cells/mouse) intraperitoneally. MPO at different doses such as 0.5, 2.5 and 5 mg. kg-1.mouse-1.day-1 and standard drug 20mg of 5 Flurouracil kg-1.mouse-1.day-1 were administered orally through gavage for 14 days to group III, IV, V and VI respectively. Anti tumor effect of MPO was assessed by observing the changes with respect to body weight, packed cell volume, viable and non-viable tumor cell count, median survival time and percentage increase in life span (% ILS). Ingestion of 5 mg of MPO produced desirable changes in cancer induced mice and it was comparable with the EAC mice treated with 5FU 20 mg/kg body weight. In addition, MPO facilitated to reverse the changes by tumor growth proving its health benefits.

Quercetin is a phenolic compound that exhibits strong antioxidant activity and they are widely found in onion (Allium cepa). The concentration of quercetin in the onion of different species or different date of purchase varies within the range of 185-634mg/ kg of fresh onion. The naturally occurring quercetins in the onion are appeared in glucose conjugate forms such as quercetin-4?-O-?-glycopyranoside, quercetin-3,4?-O-?-diglycopyranoside, and quercetin -3,7,4?-O-?-triglycopyranoside. The attachment of glucose on the molecule of quercetin has brought to two adverse effects: i) Decrease of the antioxidant activity. ii) Limit the human intestinal absorption upon oral consumption. Previous studies have suggested several methods to remove the glucose from the molecule of quercetin including the strong acid hydrolysis, organic acid hydrolysis, enzymatic hydrolysis and lactic acid fermentation.

Amaranthus hybridus and Adansonia digitata leaves were analysed for their proximate and mineral elements (potassium, sodium, calcium and magnesium) using standard methods of food analysis. Ash contents of 19.72±0.5 and 10.63±0.2% for both samples revealed that they are good mineral source. 35.30±6.3 and 45.44±8.1% of carbohydrate concentrations obtained resulted in high energy values. Potassium has the highest concentration among the mineral elements analysed with 1133±4.50 and 892±3.10mg/100g, followed by calcium with 737±2.30 and 1042±6.20mg/100g for the leaves of Amaranthus hybridus and Adansonia digitata respectively. However, the ratio of sodium to potassium values obtained from the two leafy vegetables in this study indicated that they could possibly serve to reduce high blood pressure diseases in the human body. Nutrient density (ND) greater than 100% recorded for all the elements indicated that vegetables of our study can serve as source of supplement for these mineral elements.