Quality Characteristics of Cookies Produced from Sweet Potato and Wheat Flour Blend Fortified with Brewer's Spent Grain Flour
CURRENT RESEARCH IN NUTRITION AND FOOD SCIENCE
Authors: Okpala, Laura C.; Ofoedu, Purrissima I.
Cookies were made from flour blends of 70% wheat and 30% sweet potato fortified with varying levels of brewers spent grain (BSG) flour. The BSG flour ranged between 0 and 9% of the flour weight. Cookies made with flour from 100% wheat served as the control. Studies were carried out on the functional properties of the flour blends, proximate composition, calorific values, physical characteristics and organoleptic quality of the cookies produced. Fortification of the blends with BSG flour reduced the bulk density from 1.24-1.08 g/mL and the water absorption capacity from 1.73-1.37g/g. Emulsion capacity increased from 76.10 - 83.45% and oil absorption from 2.20 - 3.66 g/g. The protein, fiber and ash contents of the cookies increased from 10.10-11.32%, 1.91-3.11% and 3.87-5.31% respectively. Cookies containing 9% BSG flour had the highest fibre content. Organoleptic studies revealed that cookies fortified with 3-6% BSG flour were more preferred than the control.
Comparison of mild alkaline and oxidative pretreatment methods for biobutanol production from brewer's spent grains
INDUSTRIAL CROPS AND PRODUCTS
Authors: Fernandez-Delgado, Marina; Plaza, Pedro E.; Coca, Monica; Teresa Garcia-Cubero, M.; Gonzalez-Benito, Gerardo; Lucas, Susana
In this study, a comparative analysis of different pretreatment strategies on hydrolysis and fermentation of brewers' spent grain for biobutanol production by C. beijerinckii is presented. Ozone (2.7% w/w, 30 min, 40-60% w/w humidity), sodium hydroxide (1-5 % w/w NaOH, 30 min, 120 degrees C, 5-15 % w/w BSG) and hydrogen peroxide (5% w/w H2O2, pH 11.5, 60-180 min, 50 degrees C, 5-15 % w/w BSG) were the pretreatments analyzed. Ozonolysis was not very effective for either the degradation of lignin or the recovery of fermentable sugars in the enzymatic process under the tested operation conditions. Maximum butanol and ABE concentrations, 5.3 +/- 0.2 g butanol/L and 6.8 +/- 0.2 g ABE/L, were observed when low moisture content was used (40% w/w). The peroxide alkaline pretreatment was found to be the most effective for BSG, when it was conducted at 5% BSG for 60 min. Under these conditions, sugar enzymatic yields of 62.8% for glucose and 28.1% for xylose and arabinose, referred to untreated BSG, and product concentrations of 11.0 +/- 0.2 g butanol/L and 13.7 +/- 0.2 g ABE/L, were achieved. The alkaline pretreatment at 15% BSG with 1% w/w NaOH also provided high butanol and ABE concentrations (7.3 +/- 0.1 g butanol/L and 8.9 +/- 0.1 g ABE/L). Both the sodium hydroxide alkaline and peroxide alkaline methods were highly successful as pretreatments of BSG for ABE production, with overall yields of 44.4 g butanol/kg BSG and 54.0 g ABE/kg BSG for NaOH pretreatment (15% BSG, 1% w/w NaOH) and 45.1 g butanol/kg BSG and 56.1 g ABE/kg BSG for H2O2 pretreatment (5% BSG, 60 min).