Asian Food Science Journal

This study investigated the effect of the processing conditions (frying temperature and time) on the thermophysical properties and product quality attributes of deep-fat fried plantain (dodo). The plantain were deep-fried at various frying temperatures (150-190 °C) and time intervals (120-240 sec). The thermophysical properties determined include specific heat, thermal conductivity, thermal diffusivity and density. The product quality attributes were moisture content, oil content and colour. The specific heat, thermal conductivity, thermal diffusivity and density of the deep-fat fried plantain ranged from 2.68 to 2.33 kJ/kgK, 0.37 to 0.33 W/mK, 1.12 to 1.36 x10-7 m2/s and 1049.50 to 1257.00 kg/m3, respectively. The quality attributes of dodo varied from 0.24 to 0.65 abs, 30.37 to 43.40% and 9.96 to 14.25% for colour, It was observed that the specific heat, thermal conductivity, thermal diffusivity and moisture content of the deep-fat fried plantain were significantly reduced as frying temperature and time increased. The colour and fat content of dodo were found to increase with increased temperature and time of frying. Outcome of the study resulted in the development of dodo with high acceptable quality characteristics. Therefore, generated data will be useful in choice of processing conditions for plantain and development of fryer.

The aim of this research was to investigate the impact of extraction solvents on the non-phenolic phytochemical profiles of selected spices (Ocimum viride, Monodora myristica, Monodora tenuifolia and Tetrapleura tetraptera) and spice-treated foods in southern part of Nigeria. The spice samples were processed into powder for antioxidant screening. The spice extracts were obtained from the samples using 5 extracting solvents [distilled water, 95 % methanol, acetone / hexane (1:1 v/v), n-hexane / methanol / acetone (2:1:1, v/v/v) and acetone / water / acetic acid (70:29.5:0.5, v/v/v)]. Water extracts were obtained from beef, pork and fluted pumpkin leaves. The alkaloid, saponin, oxalate and phytate components of the spice extracts and the spice-treated foods were evaluated using standard methods. The laboratory analyses were performed at analytical laboratory, National Centre for Energy Research and Development, University of Nigeria, Nsukka during the 3^rd quarter of 2020. The percentage yield of the extracts were low (0.32 - 0.96 %) and varied widely among extracting solvents, spices and spice-treated foods. M. myristica and T. tetrpleura had the highest yield, 0.96, in methanol extracts. Phytochemical contents differed significantly (p < 0.05) among spices, extracts of the same spice and among spice-treated foods. Spices had high contents of oxalate (2.0 – 7.0 mg/100 g), alkaloid (0.8 – 5.76 mg/100 g) and phytate (2.14 – 3.88 mg/100 g) but relatively low content of saponin (0.03 – 0.736 mg/100g). Methanol alone or in combination with other solvents extracted higher amounts of phytochemicals (0.96 %) than other solvent mixtures from the spices. Phytochemical contents of spice-treated foods were in the order: vegetable > rice > pork > beef.

Aim: This study evaluated the physicochemical, functional and pasting properties of garri fortified with soybean flour.

Methodology: Soybean flour was incorporated into the garri prior to garrification at a ratio of 10, 20, 30, 40 and 50% for samples A, B, C, D and E respectively. Sample without soybean flour served as control. Standard analytical procedure was used in the evaluation of all six samples.

Results: The pH and titratable acidity (TTA) of the samples varied respectively, from 4.59 - 6.48 and 0.08 - 0.17 % lactic acid. There was significant (P<0.05) decrease in pH with increase in soybean flour, while the reverse was the case for TTA. Swelling power, bulk density and water absorption capacity of the soybean fortified garri ranged from 8.74 - 17.81%, 0.60 - 0.80 g/ml and 13.44 – 19.43 % respectively. Control sample (100% garri) had hydrogen cyanide (HCN) content of 1.50 mg HCN/100g while samples with soybean flour had no detectable levels. Peak viscosity, trough, breakdown, final viscosity and setback varied significantly (P<0.05) from 101.19 - 399.44, 90.92 - 320.19, 10.28 - 79.25, 123.19 - 451.50 and 32.28 - 131.31 RVU respectively. Peak time and pasting temperatures ranged from 5.18 – 6.34 min and 74.28 – 92.88 ^oC.

Conclusion: The study revealed that a good quality garri can be produced with the incorporation of soybean flour up to 50%, the garri is safe for consumption as there was no HCN detected, and the decrease in viscosity provides for a soft textured, mouldable garri that is convenient for swallow.

Jams are preserved fruits and sugars which are packaged in cans or bottles for long-term preservation. The processing involves the disruption of the fruit tissue followed by heating with water and sugar to activate the pectin prior being put into containers. Jams were processed from two selected tropical fruits namely, pineapple and watermelon. The jam produced was spiced with ginger and turmeric at 5% level using a standard methods. The treatments are WA (watermelon 100%), WAG (watermelon 95% + ginger 5%), WAT (Watermelon 95% + turmeric 5%), WAGT (watermelon 95% + ginger 5% + turmeric 5%), PI (pineapple 100%), PIG (pineapple 95 % + ginger 5%), PIT (pineapple 95% + turmeric 5%) and PIGT (pineapple 95% + ginger 5% + 5% turmeric). The proximate, physiochemical, antioxidant, total phenolic, color and sensory characteristics of the spiced jams were determined using standard analytical procedures. The proximate result showed that the moisture content of the samples ranged from 3.61-20.55% for Watermelon jam (WA) and reference sample (CNTP); protein 0.50-5.16% for (CNTP) and watermelon-ginger jam (WAG); fat and ash contents were 0.21-2.55% and 0.38-1.53% for (CNTP) and pineapple jam (PI) respectively. The pH of the spiced jam ranged from 3.10-3.40 for (CNTP) and (WAG) while the sugar brix ranged from 69.80-79.50° brix. The titratable acidity of the samples ranged from 1.03-1.06 g/ml for pineapple-turmeric jam (PIT) and (CNTP).The TSS/TTA ratio was 52.88 and 5.39 for (CNTP) and (WA) respectively. The antioxidant properties of the sample ranged between 31.39-50.67% for (WA) and (PIG). Total phenolic content was 0.14-0.25 MM GAE/ 100 ml for watermelon jam (WA) and (PIT). The L*, a* and b* values for the samples ranged from 23.23-33.16, 1.05-6.69 and 3.35-13.55. The result for sensory scores of the spiced jams ranged from 5.66-7.98 and 6.20-7.88 for color and taste respectively while the mouth feel was 5.05-7.46. The overall acceptability scores ranged from 6.40-7.90. Conclusively, pineapple and watermelon jams spiced with ginger and turmeric were nutritious and acceptable, however, pineapple-ginger jam was most nutritious and acceptable, hence, pineapple-ginger jam can be utilized as a functional food and can also contribute to the improvement of Nigeria food composition database.

Aim: Cane sugar (Saccharum officinarum) and (Cocos nucifera) jaggery are prominent sweeteners. The aim of the this study is to evaluate Glycemic Indices (GI) of cane sugar and coconut jaggery using healthy human subjects.

Place and Duration of Study: The research was conducted as a collaborative project with Coconut Research Institute Sri Lanka and National Hospital Colombo Sri Lanka, between 2019 to 2020.

Methodology: Starch fractions (Total starch - TS, Resistant starch – RS and Digestible starch – DS) and sugar profile of two test foods were analyzed. Thirty six (n=36) healthy volunteers were recruited and were subjected to health screening. Fifty grams of digestible carbohydrate containing test food portions were given for each subject who had been fasting for 8 - 12 hours. Intravenous blood samples were collected to analyze blood glucose concentration and GI of food.

Results: Cane sugar contained high percentages of TS (95.86 ± 1.58%), DS (95.73 ± 1.59%) and RS was just 0.13± 0.02%. Coconut jaggery contained a lower percentage of sucrose (76.12±1.62%) and glucose (5.22±0.11%). Healthy volunteers (25.95±3.62 years) whom were having healthy fasting blood glucose concentrations (73.54±8.89 mg/dl) and HbA1c (5.05±0.35 %) were tested with glucose, and the two test foods.

Conclusions: There was no significant difference (P>0.05) between blood glucose response curves and GI of coconut jaggery (65.19±36.53) and cane sugar (60.76±35.80), where both can be considered as moderate GI sweeteners.

Oil contents through analysis of proximate composition of the seeds of six legumes were investigated in order to assess the quality attributes of some of their oils. These legumes were cowpea (Vigna unguiculata), bambara groundnut (Voandzeia subteranea), yam bean (Sphenoostylis stenocarpa), oil bean (Pentaclethra macrophylla), soybean (Glycine max) and groundnut (Arachis hypogaea) seeds. The oil yields ranged from 2.5% in cowpea to 40.3% in groundnut seeds. Crude protein contents ranged from 20.86% in bambara groundnut seeds to 43.02% in soybean seeds indicating they are good sources of protein. Cowpea seeds had highest content (57.76%) in carbohydrate, followed by yam bean (56.54%) and bambara groundnut (51.64%), while oil bean had the lowest value of 6.92%. The physicochemical properties of the oils from soybean, oil bean and groundnut seeds were further examined since their oil yields were above 10.00%. Seventy grams of oil in each case were extracted from these legumes for these analyses. The specific gravity ranged from 0.910 in oil bean oil to 0.917 in soybean oil. Oil bean oil, with highest values in moisture content (0.75 %) and peroxide value (21.2 mg/g oil) had highest saponification number of 306.86 mg/g oil while soybean oil with lowest values both in moisture content (0.43 %) and peroxide value (9.80 mg/g oil) had the lowest saponification number of 187.94 mg/g oil. Free fatty acid ranged from 0.17 in soybean oil to 0.48 in groundnut oil. Iodine value was highest (98.22 mg/100g) in soybean oil, followed by oil bean oil (98.22 mg/100g) and was lowest (93.40 mg/100g) in groundnut oil. These results obtained highlighted the potentials of these three oils in the manufacture of soaps, cosmetics, paints, confectioneries, margarines and edible oils. The results also maintained that soybean oil exhibited the best physicochemical properties amongst them and thus could be used better as edible oil and for industrial applications.

Six varieties of green leafy vegetables, namely, Amaranthus hybridus, Corchorus olitorius, O. gratissimum, Talinum triangulare, Telfaria occidentalis and Vernonia amygdalina were estimated in their raw, steamed and boiled forms for their mineral compositions. The effect of two different cooking methods (steaming i.e. water blanching and boiling) on fresh leafy vegetables were also evaluated. The mineral contents of fresh leaves of the vegetables were determined using Energy Dispersive X-ray Fluorescence techniques (EDXRF). The results from EDXRF analysis of mineral contents of the six leafy vegetables revealed that fresh, steamed and boiled C. olitorius had the highest quantity of K (133.5, 131.5 and 91.2 mg/100 g) and Zn (28.9, 28.4 and 21.4 mg/100 g) respectively. The fresh, steamed and boiled T. occidentalis had the highest quantity of Ca (124.2, 122.2 and 80.3 mg/100 g), Na (102.2, 100.6 and 71.1 mg/100 g) and Mg (324.5, 319.2 and 225.5 mg/100 g) respectively, while the fresh, steamed and boiled A. hybridus had the highest quantity of Fe (48.6, 47.7 and 29.1 mg/100 g) respectively. The results of percentage loss of mineral composition revealed that almost 40 % of minerals in boiled vegetables was lost, while the amount lost in steamed vegetables was < 2 %. The results obtained from evaluation of sodium/potassium (Na/K) ratio showed that all fresh and steamed leafy vegetables have the same values but the boiled leafy vegetables gave different values. The results have shown that vegetables could serve a better source of some important minerals that can contribute qualitatively to the nutritional need of humans. Based on the results from the processing of vegetables, we suggest that the daily nutritional needs can better be acquired by consuming the steamed processed vegetables rather than consuming the boiled processed vegetables, which would also probably reduce high blood pressure diseases.