Influence of roasting conditions on physicochemical and fatty acid profile ofraw and roasted cashew kernel (Anacardium occidentale) grown in Nigeria

This study aimed at evaluating the effect of roasting conditions on some physicochemical and nutritional properties of cashew nut lipid fractions at different temperature (100–160ᵒC) and time (20–60 min). Raw and roasted cashew nuts were also analyzed for their composition in fatty acid by GC-FID. Physicochemical properties of the oil showed that the oil yield of roasted cashew nut oil (56.67-31.67%) was significantly higher compared to unroasted oil (47.43%). Also, cashew nut oil with mean values revealed that acid (12-0.86 mg KOH/g of oil); saponification value (138.10-169.06 mgKOH/g of oil), iodine value (55.50-36.19 mg of I/100g of oil); TBA(0.012-0.18mg); p-anisidine value (0.55-0.66); peroxide value (7.26-3.05 meq/kg) and free fatty acid (1.07-1.50 % oleic acid) which indicated that cashew nut oil is edible, non-drying and may not be suitable for soap making. Results of GC-FID analysis of the ethyl esters of saturated and unsaturated fatty acid of raw and roasted cashew nut showed that unsaturated fatty acids represented 60.57% for unroasted samples with roasted samples (79.67–83.67%) while saturated fatty acids recorded (16.11–37.65%). The fatty acid composition of the oils shows the presence of four main fatty acids: palmitic (9.25–29.50%); stearic (4.4–9.34%); oleic (34.75–65.60%); and linoleic (1.35–20.66%) with high oleic to linoleic ratio associated with high oil stability. The order of increase is oleic > linoleic > palmitic > stearic in all the samples irrespective of roasting conditions. The result showed that minor changes occur in the fatty acids composition as the roasting temperature and time increased. It was concluded that the heat treatment used does not significantly affect the fatty acid profile content of cashew nuts preserving its antioxidant activity along with other bioactive compounds contained therein

The influence of roasting conditions on volatile flavour compounds in raw and roasted cashew kernels (Anacadium ocidentale) grown in Nigeria

The use of inappropriate temperature-time combinations during the roasting of nuts could lead to quality defects, such as burnt taste, short shelf-life, rancidity, and poor flavour. In this study, cashew kernels were roasted in a forced airflow-drying oven for 20, 40, and 60 min at 100, 120, 140, and 160 °C. The products were evaluated for volatile flavour compounds and the sensory evaluation of the roasted cashew kernels at different roasting conditions. The volatile fraction was isolated using the combined steam distillation–extraction procedure and identified by gas chromatography–flame-ionization detection (GC-FID). The consumer acceptability test was carried out by 100 panellists using nine point hedonic scales to assess preferences for like or dislike, colour, taste, texture, flavour, and overall acceptability. It was found that there were significant differences in flavour compounds between the different conditions of roasting. Twenty-nine volatile compounds were identified in both fresh and roasted cashew kernels comprising five main classes, which consist of 12 hydrocarbons, eight aldehydes, four ketones, three alcohols, and one acid. The volatile compounds (mg/100 g) ranged from 5.03x10-2 to 1.20 (2-butanone), 7.46x10-6 to 1.85 (hexanal), 8.91x10-6 to 1.94 (acetone), 6.74x10-1 to 2.24 (benzaldehyde). The amount of generated volatile compounds increased as the roasting temperature and time increased. The consumer acceptability test revealed that samples roasted for 40 or 60 min at 140 °C produced the most acceptable product in terms of all the measured attributes. The study showed that the roasting conditions produced acceptable cashew kernels of desirable colour and superior flavour quality that enhance direct and commercial utilization

Nutritional profile, protein quality, and biological value of raw and roasted cashew kernels (Anacardium occidentale) grown in southwest Nigeria

Cashew kernels are one of the most concentrated food products due to their fat and protein content and they are used in puddings and bakery products, hence the determination of their protein quality is an important nutritional factor in dietary protein requirements. Therefore, the study aimed at evaluating the effect of roasting conditions on the protein quality of cashew kernels at the temperature of 100–160 C and time (20–60 min), and then analysing for the amino acid profile by GC-FID; protein predicted efficiency ratio (P-PER), essential amino acid index (EAAI), and the Isoelectric point (pI). About 2.0 kg of dried cashew kernels used were defatted using chloroform/methanol (2:1/v/v) as the extraction solvent and then analysed using standard methods. The results showed that seventeen amino acids were present in cashew nuts, where glutamic acid (15.27g/100gN); aspartic acid (12.20g/100gN); lysine (6.09g/100g N), and phenylalanine (5.06g/100g N) were predominant. Eight essential amino acids were present in cashew kernels, the highest value of 7.33g/100g were for lysine (6.09g/100gN); 1.70g/100gN (histidine); 3.42g/100gN (threonine); 3.63g/100gN (valine); 3.57 g/100gN (isoleucine); 7.33g/100gN (leucine); and 5.06g/100gN (phenylalanine). Roasting reduced the lysine content by 18.4%, phenylalanine by 12.06%, and aspartic acid by 41.4% at 160°C for 60 min, while serine (58.9%); glutamic acid (19.7%); arginine (47.4%), and histidine (115.9%) were increased, suggesting that cashew nuts contain high quality protein. P-PER results were 2.57 (raw), 171-2.61 (roasted); EAAI is 1.55(raw) and 1.38-1.55 (roasted), BV% is 76.15 (raw) and 67.61-76.89 (roasted); the Isoelectric points were 4.65 (raw) and 3.87- 4.54 (roasted), The Leu/Ileu ratio was 2.12 (raw) and 2.01-2.67 (roasted). It was concluded that the heat treatment used does not significantly affect the amino acid profile of cashew kernels, thus preserving their nutritional quality

Influence of temperature and thickness on thin layer drying characteristics of onion (Allium cepa L.) varieties and rehydration capacity

Nonlinear regression analysis was conducted for thin layer drying characteristics of two onion varieties (white and red) and some quality characteristics were also examined. The experimental data obtained at drying temperatures of 40, 50, and 60 oC and thicknesses of 2, 4 and 6 mm, was subsequently fitted into four commonly used models (Henderson and Pabis, Lewis, Page, and logarithmic). Moisture diffusivity and activation energy ranged from 8.9 × 10-10 to 8.4 × 10-9 m2/s and 55.98 to 65.68 KJ/mol, respectively. Significant differences (p<0.05) were observed in the colour profile and rehydration ratio. The optimum desirable colour was obtained at 50 oC with 2 mm thick onion slices and the observed higher rehydration ratio indicates good quality of dried onions. Among the four selected drying models, the Page model predicted optimally (R2 > 0.9) and was found to be better in describing dried onion varieties, while the Lewis model provided the least fit

Influence of hydrocolloids addition (carboxymethylcellulose and guargum)on some quality attributes of wheat and high quality cassava flour and itsbread making potentials

High quality cassava flour (HQCF) is now widely used production of baked foods in Nigeria but bread quality is impaired when it is used in the bread formulation. In order to overcome this problem, six breads samples were produced from wheat/HQCF/hydrocolloid:T0100%wheat flour(control);T190:9:CMC;T290:9:GG;T3,80:18:CMC;T4,80:18:GG;T570:27:CMC;T670:27:GG. The flour blends were analyzed for functional, colour and pasting properties while breads characteristics and sensory evaluation were performed in order to assess effect of hydrocolloids on bread. The results showed composite flour with hydrocolloids had the highest bulk density (0.704g/ml), water absorption capacity (2.98m/g), least gelation concentration (4.4g/g), oil absorption capacity (0.71m/g), while control had the highest swelling capacity (1.68g/g). Significant differences at p<0.05 were found on the pasting properties of addition of hydrocolloids with lower pasting temperature (71oC) and time (6.08 min). Bread quality attributes such as loaf volume, specific loaf volume, oven spring, crust colour, crumb colour and firmness of the fresh breads significantly improved with the addition of hydrocolloids compared with bread produced without improvers. The results show that high quality cassava flour could be incorporated up to 18% with carboxymethylcellulose at 2% level without affecting its overall acceptability and thereby enhance the potential for using locally produced flours in bread baking. Sensory score of bread from the addition of hydrocolloids were all acceptable by the panelist. The addition of hydrocolloids could be used as an effective means of improving the quality of gluten free bread

Design and construction of a mechanized charcoal-fueled corn roaster

The economic situation in most developing countries has left farmers and processors operating at small scale and under unhygienic environment. The productivity is often too low to justify labour and time investment. With respect to the challenges particularly associated with roasting of corn, a roaster was designed, constructed and its performance evaluated. The mechanized charcoal fueled corn roaster consists of a frame, roasting unit, charcoal tray, air blowing unit and a power transmission system. The functional efficiency of the machine at different roasting temperatures of 100oC, 130oC and 150oC ranged between 88% and 94%, while the roasting capacity and roasting time ranged between 40 and 54 fresh corns per hour in 22 and 30 min, respectively. The developed roaster can effectively address the need of rural dwellers as well as small and medium scale processors, which would subsequently contribute to economic empowerment and alleviation of food insecurity in areas where this food product is frequently consume