Ultrasonic Extraction and Characterization of Dietary Fiber from Different Oat Cultivars

Abstract

Oat is a 5th among cereal crop predominately cultivated as forage equipped with a plethora of bioactive moieties, having various physiological functions. Oat cultivars including Avon, PD2LV65, S-2000, SGD-2011 and SGD- 81 were selected and characterized for physical, chemically, nutritional and functional properties. The highest fraction of crude fiber was observed in oat cultivar SGD-81 (17.83 g/100g), whereas oat cultivar Avon excelled in crude protein content (12.69 g/100g). The maximal fat content (6.67 g /100g) was shown by oat cultivar. The highest moisture content (9.29 g /100g). The highest ash content (6.02 g/100g). Oat cultivar S-2000 had the maximal NFE (60.78 g/100). The entire fractions were calculated on dry weight basis. Maximum TGW (36.74 g) was shown by oat cultivar S2000. The maximal zinc contents (33.21 ppm) and iron contents (176 ppm) were shown by the oat cultivar Avon. Oat cultivar Avon showed the maximal L/B ratio (2.93) and bulk density of 0.76 g/cc. Oat cultivar SGD-81 showed maximum emulsion stability (73.13 %), water absorption capacity (188.33%) and oil absorption capacity (218 %). Oat cultivar S-2000 showed maximum foaming capacity (20%) and oat cultivar SGD-2011 showed the maximal emulsion activity (56.84%). Oat cultivar SGD-2011 showed the maximal fraction of amino acid 105.67 g/kg, whereas S-2000 showed the fraction of amino acid (99.13 g/ kg). Oat cultivar SGD-81 showed the maximal total flavonoid contents (1147.08 mg of QE/100 g DW) and total phenolic contents (101.56 mg GAE/100 g DW). Oat cultivar SGD-2011 showed maximum flavonol contents (697.5 mg of GAE/100 g DW) and anthocyanin contents (2.87 mg of C3G /kg). The highest DPPH activity (55.88 %) was shown by the oat cultivar SGD-81. 3 D response surface diagram and contour plot expound the interactions and allowed determination of the optimal levels of variables. Elliptical contour line was observed that showed factors were significant; while the circle showed non-significant. The optimal conditions for factors were obtained through optimization function of software. Time varied from 24.02 to 28.63 min, temperature varied from 24.23 to 27.44℃ and amplitude varied from 67.11 to 76.51. Using these independent variables, the yield varied from 33.3118 to 37.2526 g/50g, TDF varied from 10.1696 to xxvi 14.6882 g/20g, IDF varied from 5.4111 to 10.6247 g/20g and SDF varied from 3.3155 to 4.0731 g/20g, respectively. The extracted fiber from all oat cultivars was characterized by FTIR, SEM with EDX, TGA, DSC, XRD and surface area and pore size analysis. SEM with EDX indicated that the extracted fiber is an important source of essential micronutrient especially iron, zinc and silicon. Thermal analysis of the extracted fiber indicated that it had good thermal stability up to 250 ℃, hence can be used in various food, feed and nutraceutical products. DSC indicated no crystallization and melting phase that is indicative of purity of dietary fiber. X- ray diffraction was observed between 15 to 25 ℃. Biological efficacy study indicated that fiber concentration has no significant effect on CBC, while it had significant effect on BUN, SGPT, SGOT, HDL, LDL serum creatinine, cholesterol. Toxicological study of the tissue taken from subject indicated no carcinoma, edema, inflammation and abnormal growth. Dietary fiber significantly (p≤0.05) reduced serum glucose level of diabetic rats. Ultrasonically extracted fiber from oat cultivar SGD81 was incorporated into biscuit dough to assess the rheological properties. Mixograph, Farinograph and RVA analysis showed that different level of fiber incorporation in flour had significant effect on dough development and stability significantly (p≤0.05). Spread ratio of fiber incorporated biscuits varied from 2.59-5.79 ranged with increase in level of oat fiber. Color tonality of biscuits significantly decreased its L*, b*, c* and h*factors, while a* factor increased with level of fortification. Textural study of biscuits showed that less shear force is required to break the biscuits with maximum oat fiber incorporation. Oat can be effectively used in food and feed industry for bearing maximum protein contents. Oat cultivars are also loaded with zinc and iron and its addition in food may play important role in overcoming these micronutrient deficiencies. Value addition of oat crop may have an ample opportunity purification and export of dietary fiber especially soluble dietary fiber. SGD2011 is identified potential source of antioxidants and oat cultivar SGD81 distinct source of dietary fiber.