Studies of some quality parameters of dried paraquetina nigrescens. L. leaf
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Date
2023
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Department of Food Science and Technology, Faculty of Technology, Obafemi Awolowo University.
Abstract
The study investigated the drying kinetics of African parquetina (Parquetina nigrescens) leaves at three different temperatures and evaluated the effect of various drying conditions on its phytochemical, proximate, antioxidant and mineral properties. It also assessed the storage stability of the dried leaves. These were with a view to examining
the effect of using various drying temperatures on the chemical composition and rehydration assessment of Parquetina nigrescens leaves. Freshly harvested Parquetina nigrescens young leaves were destalked, washed, drained and sliced. Leaves were sun dried and oven dried at 50, 60 and 70 oC and weighed at 5, 10, 15, 30 and 60 mins intervals until a sample weight remained unchanged. The dried samples were pulverized into fine powder particle size. Drying data obtained were fitted into five thin layer drying models (Newton, Page, Henderson and Pabis, Logarithmic and Modified Henderson and Pabis). The phytochemical, proximate, mineral and antioxidant properties in both fresh and dried Parquetina nigrescens leaves were determined in accordance with standard procedures. Rehydration capacity was determined at four temperature
levels of 30, 60, 70 and 80 o C. The data generated in this study were examined using appropriate descriptive and inferential statistics. The results obtained showed that
moisture content reduced as temperature and time increased. The effect of drying temperature on the leaves was significant (p<0.05) up to 105 min after which the drying weight was constant. The proximate composition of the dried leaves indicated; crude protein, total ash, moisture content, crude fibre, fat and carbohydrate content in the range of 5.09 - 5.85%; 51- 0.64%; 9.14 - 9.55%; 1.75 - 1.93%; 1.10 - .24% and 79.47 - 82.06% respectively. For mineral constituents, it was found that: calcium, phosphorus, sodium, magnesium, zinc, copper and iron were in the range of(5.05-5.14, 0.08-0.81, 80.18-87.17, 3.31- 4.64, 0.67-8.02, 1.33- 2.11 and 0.22-0.96 xvii mg/100g, respectively). The antioxidant properties of the leaf samples indicated that Ferric Reducing Power (FRAP), Metal Chelation Activity (MCA) and1,1diphenypicylhydrazine (DPPH) are in the range of 0.27- 0.40, 53.16 -71.45 and 20.14 - 37.67, respectively. The pH of the stored dried leaves ranged between 6.15 - 7.56. The phytochemical properties present, indicated (flavonoid 151.41-170.77mg/100g), (phenol12.50 –17.81mg/100g), (glycosides 0.62 –5.54mg/100g), (alkaloid 0.22-0.98mg/100g), (triterpene 165.08-185.92mg/100g
(steroid111.1 - 127.0mg/100g), (tannin 2.6-6.00mg/100g), (saponin 0.94- 1.01mg/100), (terpenoid 1.10 - 17.81mg/100g) and (coumarin 4.12--15.43mg/100g) respectively. In addition, it was confirmed that storage time lower the rehydration capacity and high in rehydrating temperatures, increased the rehydrating capacity of the dried leaves. The study concluded that sundried samples had better quality attributes than oven dried samples while oven dried leaves at 70 o C indicated the best quality out of the three temperature used.
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xvii, 109p
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Citation
Ayodele, E.A. (2023). Studies of some quality parameters of dried paraquetina nigrescens. L. leaf. Department of Food Science and Technology, Faculty of Technology, Obafemi Awolowo University.