Effect of cooking and smoking methods on proximate composition, lipid oxidation and mineral contents of Polypterus bichir bichir fish from far-north region of Cameroon.

The objective of this study was to evaluate the effect of different cooking and smoking treatments on proximate composition, lipid quality and mineral content of Polypterus bichir bichir, a fish consumed in Far-North Region of Cameroon. Results revealed that the proximate composition was significantly (P < 0.05) affected by treatments: except boiling, all the others treatment reduced significantly (P < 0.05) moisture content of fish while lipid and protein were significantly increased. After processing, the free fatty acids, peroxide and thiobarbituric acid reactive substances values (TBARS) were increased. Iodine value of all treated samples was significantly (P < 0.05) decreased. The combined treatments (frying + boiling and smoking + boiling) negatively affected the lipid quality of fish. Boiling caused significant losses in the mineral contents of fish while smoking treatment led to an important increase of its mineral contents. Steaming appeared to be the best processing method for cooking fish concerning the lipid stability.

Effect of boiling and oven roasting on some physicochemical properties of sunflower seeds produced in Far North, Cameroon.

The effects of different processing methods on proximate composition, total phenolic content, antioxidant activity, lipid oxidation, and mineral contents of sunflower seeds produced in Far North Region of Cameroon were evaluated. Mean moisture, ash, lipid, protein, fiber, and carbohydrate contents of raw sunflower seeds were 6.60%, 2.55%, 44.65%, 20.17%, 4.08%, and 21.25%, respectively. The changes in moisture, ash (excepted in boiled samples), lipid, protein, fiber, and carbohydrate (excepted in roasted samples) were found to be significant for all cooking methods. Ash and lipid contents of samples roasted at 120°C were found to be significant when compared with other cooking methods. Antioxidant activity increased with treatment. After processing, the acid, peroxide, and thiobarbituric acid values increased significantly, whereas iodine value decreased. The roasting process improved the induction time, and samples roasted at 120°C were found to have the highest induction time (2.29 ± 0.09 hr). Raw sunflower seeds were good sources of potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), zinc (Zn), and manganese (Mn). Increase in contents of Ca, Mg, Zn, Cu, and Fe was observed during processing. Roasting compared with boiling appeared to be the best cooking method of sunflower seeds concerning nutrient content, antioxidant stability, and lipid stability.

Effect of oven and sun drying on the chemical properties, lipid profile of soursop (Annona muricata) seed oil, and the functional properties of the defatted flour.

Soursop seeds present a potential source of edible oil production. This work was aimed at determining the effect of oven and sun drying on the chemical properties and lipid profile of soursop seed oil as well as the functional properties of the defatted seed flour. The chemical properties, lipid profiles, and functional properties of soursop seeds dried for 0, 6, 12, 18, 24, and 30 hr, and 0, 1, 3, and 5 days, respectively, in the oven and on the sun using time T0 as the control sample were determined using oil quality indices, gas phase chromatography, and functionality tests for flours, respectively, with a view of highlighting the potentials of the defatted seed. The result of the study revealed that the chemical properties of oils for oven-dried and sun-dried seeds changed with drying technique and time, with iodine value being the more affected parameter, and peroxide value (PV) being the least. The control exhibited the highest free fatty acids (FFAs), peroxide value (PV), thiobarbituric acid (TBA) value, and saponification value compared with dried samples. The fatty acid profiling showed that the predominant fatty acids were C18:1n-9, C18:2n-6, and C16:0 and that unsaturated fatty acids (UFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and omega-fats were not significantly affected by the oven drying time. The mean PUFA content ranged from 31.72% with sundried seeds to 30.92% after 30 hr of oven-drying and was not significantly affected by the drying technique. The oils contained more n-6 (30.60%) fatty acids than n-3 (1.12%). The PUFA/SFA ratios [1.14-1.37] as well as the Atherogenic index (AI) [0.25-0.27] were acceptable because of the recommended range of FAO/WHO. PUFA/SFA, n-6/n-3, and Atherogenic index (AI) did not change much with the sun-drying technique compared with oven-drying. Flours from sun-dried seeds had better functional properties than oven-dried and more than 3 different types of proteins (based on isoelectric points of proteins). It can be concluded that soursop seed contains good quality oil, which can be exploited to improve nutrition. Manufacturers of animal feeds should explore the agro-industrial use of its oil and defatted seed flour.

Nutritional, sensory, physico-chemical, phytochemical, microbiological and shelf-life studies of natural fruit juice formulated from orange (Citrus sinensis), lemon (Citrus limon), Honey and Ginger (Zingiber officinale).

Orange (Citrus sinensis), lemon (Citrus limon), ginger (Zingiber officinale) and honey contain nutrients and phytochemicals that are beneficial to health. Most of the available fruit drinks are artificial and may contain a lot of chemicals which could be unhealthy and detrimental to the health of the consumers. This work was aimed at formulating a healthy fruit drink from the combination (blend) of orange, lemon, ginger and honey for the development of a new product. Thirty (30) different juice blends (formulae) were made and subjected to sensory evaluation, from which five best formulated juices were selected using a 9 point hedonic scale. These were then subjected to physicochemical, nutritional, phytochemical, microbiological analyses and shelf-life studies. The results of the study showed pH (3.40-4.90), Vitamin C (0.04-0.06 mg/mL), titrable acidity (0.04-0.21 citric acid mg/100mL), total soluble solids (2.90-20.69%), reducing (0.41-1.44 mg/mL) and non-reducing sugar (0.21-2.06 mg/mL). The moisture, protein, fat, ash, fibre and available carbohydrate contents ranged from 79.31-97.10 %, 0.01-0.56g/100mL, 0.05-0.11g/100mL, 0.51-1.13g/100mL, 0.01-0.09g/100mL and 16.39-22.99g/100mL respectively. The macro (K, Ca, P, Na) and micro (Zn, Fe) minerals varied differently with Potassium (K) being the most abundant. Amongst the five best formulated juices, F22 (5% lemon juice) was the most organoleptically accepted. On the other hand, F21 (10% lemon juice + sugar) which had the least overall acceptability amongst the five, was shown to be the most nutritive.

In vitro antifungal, antibacterial activities and nutritional value of nine Cameroonian edible vegetables.

BACKGROUND: The high medicinal potential of plants, including edible vegetables, is well documented. Vegetables can afford significant health benefits to consumers, depending on their medicinal properties and nutritional value. This study analysed the antimicrobial activity and nutrient contents of nine commonly consumed Cameroonian vegetables and spices for which such information is at present limited. METHODS: The antimicrobial activity of the methanol extracts of the vegetables was evaluated by disc diffusion and microdilution methods against three tomato fungi and two pathogenic bacteria species. RESULTS: The inhibition zones against fungi ranged from 10–21 mm; Irvingia gabonensis and Apium graveolens showed the highest zones with dose-dependent activity against Fusarium solani and F. oxysporum. The inhibition zones against bacteria ranged from 8–12 mm with Allium porrum having the highest inhibition zone (12 mm). Irvingia gabonensis seeds had the lowest minimum inhibitory concentration (MIC) of 6.25 mg/mL against F. solani and also had the lowest MIC of 2 mg/mL against S. aureus. Proximate composition and mineral analysis were carried out on the most active antimicrobial vegetables, I. gabonensis seeds and A. graveolens. I. gabonensis seeds were rich in lipids (69.90 ±0.14%) while A. graveolens leaves were rich in protein (35.35 ±0.49%). For macro minerals, phosphorous had the highest concentration in I. gabonensis seeds (359.67 ±1.89 mg/100 g) and A. graveolens leaves (622.14 ±2.69 mg/100 g). Iron content was the highest of micro minerals in I. gabonensis seeds (276.51 ±1.41 mg/100 g) while zinc concentration was   the highest in A. graveolens leaves (16.86 ±0.27 mg/100 g). CONCLUSIONS: This study has shown that three of the nine Cameroonian vegetables, I. gabonensis seeds, Apium graveolens and A. porrum, may potentially offer both antimicrobial and nutritional benefits to consumers. Consequently, further studies should be conducted to ascertain the effect of cooking and other factors in order to maximize these benefits.

Alteration of the lipid of red carp (Cyprinus carpio) during frozen storage.

The aim of this study was to determine the oxidative stability of oil extracted from red carp fish frozen up to 9 months at -18°C. To assess oil stability of red carp fish, the analytical indexes and Fourier transform infrared (FTIR) spectroscopy were used. These methodologies used provided similar conclusions. Before frozen storage, the composition of fatty acids showed that red carp oil is a good source of polyunsaturated fatty acids (PUFAs) such as linoleic acid (C18:2ω-6: 5.29% of total fatty acid), linolenic acid (C18:3ω3: 3.53% of total fatty acid), arachidonic acid (C20:4ω6: 3.68% of total fatty acid), eicosapentaenoic acid (C20:5ω-3, EPA: 4,06% of total fatty acid), and docosahexaenoic acid (C22:6ω-3: 3.02% of total fatty acid). During frozen storage, the free fatty acid and peroxide value increased, respectively, from 1.35% to 8.06% in oleic acid and 3.77 to 18.62 meq O2/kg in lipid, while the ratio of PUFA/SFA and polyene index decreased, respectively, from 0.58 to 0.25 and 0.30 to 0.09. The triglycerides also decreased with frozen duration. Therefore, for good fish quality, red carp fish must be stored for <3 months at -18°C.

Effect of traditional and oven roasting on the physicochemical properties of fermented cocoa beans.

The objective of this study was to determine the effect of oven and traditional roasting on the polyphenol content, antioxidant activity, lipid quality, proximate composition and mineral content of fermented cocoa beans. Results showed that traditional roasting significantly decrease (p < 0.05) the polyphenol content and antioxidant activity of cocoa beans. The analysis of oil showed that oven and traditional roasting significantly increase (p < 0.05) the peroxide and thiobarbituric acid values of cocoa butter and that traditional roasting samples were the most deteriorated. Oven and traditional roasting for 10 min reduce the iodine value of the oil, but increase its acidity. The proximate and mineral composition of cocoa beans was also seriously affected during cooking. Drying and oven roasting for 5 and 10 min; and drying and traditional roasting for 5 min appear to be the best processing methods of cocoa beans for production of cocoa based foods like chocolate.

Effect of Boiling and roasting on lipid quality, proximate composition, and mineral content of walnut seeds (Tetracarpidium conophorum) produced and commercialized in Kumba, South-West Region Cameroon.

The effect of boiling and roasting on the lipid quality, proximate composition, and mineral content of African walnut seeds (Tetracarpidium conophorum) was assessed. Results indicated that the quality of walnut oil significantly (p < .05) reduces with the treatments. Oils extracted from DBWN 60 min (Dried and boiled walnuts 60 min) and FBWN 60 min (Boiled fresh walnuts 60 min) were the most altered. The proximate composition and mineral content of walnut seeds was also significantly affected (p < .05) by the treatments. This study reveals that, thermal processing has significant effects on the nutrients and quality of lipids of walnut oil. DTRWN 60 min (Dried and traditionally roasted walnuts 60 min), DORWN 60 min (Dried and oven roasted walnuts 60 min), and TRFWN 30 min (traditionally roasted fresh nuts 30 min) are the best methods for cooking walnut because they preserve the quality of its lipids and some of the nutrients.

Effect of smoking and refrigeration on lipid oxidation of Clupea harengus: A fish commonly consumed in Cameroon.

Changes in lipids of herring (Clupea harengus) muscle during different smoking methods and 9 days of refrigeration at 4°C were investigated. The proximate analysis of raw herring revealed that the total lipid, the total protein content and the crude ash were 10.20%, 69.43%, and 19.42%, respectively. The results also indicated that during all processing free fatty acids (FFAs) and peroxide value (PV) increased, whereas iodine value (IV) and total triglycerides decreased. The change were more significantly (p < .05) during unbleached + hot smoking and refrigeration at more than 6 days. All these modification decrease the nutritional value of herring. Bleaching combined to smoking and refrigeration at <6 days had more desire effect on lipid oxidation of herring compared to other treatments. The fish obtained in these conditions are more suitable for feeding heath nutrition.

Effects of boiling and roasting on proximate composition, lipid oxidation, fatty acid profile and mineral content of two sesame varieties commercialized and consumed in Far-North Region of Cameroon.

The aim of this study was to determine the effect of boiling and roasting on the proximate, lipid oxidation, fatty acid profile and mineral content of two sesame seeds varieties. The proximate composition was significantly affected (P<0.05) during treatments. The minerals of seeds roasting at 120°C for 10min were significantly decreased. The free fatty acids content of sesame oil after processing was significantly increased (P<0.05). Iodine and peroxide value were also affected by processing. Totox and p-Anisidine values were significantly increased during processing. The fatty acids composition a little modified during processing, and roasting at 180°C for 10min mostly affected the polyunsaturated fatty acids for all sesame varieties. C16:0, C18:0, C18:1 and C18:2 were quantitatively the most important fatty acids in sesame oil. Boiling appeared to be the best processing method for cooking the two sesame varieties concerning oxidative stability and fatty acid profile.