Optimization of oil extraction from olive pomace using response surface methodology
A statistical methodology, combining Plackett–Burman design with Box–Behnken design, was applied to optimize the oil extraction process from olive pomace using hexane as solvent. Plackett–Burman design was used in the first step to evaluate the effects of five independent variables on the oil extraction yield. Temperature of extraction, time of contact, solvent-to-solids ratio and moisture content of the olive pomace were identified as significant independent variables and were further optimized by using response surface methodology based on Box–Behnken design. The optimized conditions to maximize the yield were as follows: extraction temperature at 33 ℃, contact time at 10 min, solvent-to-solids ratio at 3.5 mL/g and moisture content at 13%. The experimental value of the yield (5.98%) at these optimum conditions was found in perfect agreement with the value predicted by model (5.80%).
EFFECT OF EXTRACTION VARIABLES ON CONSUMER ACCEPTABILITY OF COCONUT MILK : A RESPONSE SURFACE APPROACH
Coconut milk is widely utilized in the food industry due to its functional roles, yet, to our knowledge, the optimal extraction conditions have not been established. The aim of this study was therefore to determine the effect of extraction variables on the sensory attributes of coconut milk with a view to determining the optimal extraction conditions. A Central Composite Design (CCD) of Response Surface Methodology (RSM) was employed to study the effect of extraction variables (extraction time, temperature and particle size of coconut meat) on the sensory attributes of coconut milk (CM). Regression models were generated and adequacy tested with lack of fit and coefficient of determination (R). The results showed that quadratic model as the highest order model with significant term that could describe the effect of extraction variables on sensory attributes of CM. The R for appearance, taste, aroma, consistency and general acceptability were 0.9306, 0.9461, 0.9787, 0.9649 and 0.9939 respectively; which indicated that a higher proportion of variations in sensory attributes were explained by quadratic model. Extraction time, extraction temperature and particle size of coconut meat had significant effect on appearance, taste, aroma, consistency and general acceptability of CM. The optimum extraction time, extraction temperature and particle size of coconut meat were 14.755 min, 40.0 C and < 1617 μm respectively, which gave panel scores of 8.09, 8.43, 7.69, 7.16 and 8.26 for appearance, taste, aroma, consistency and general acceptability, respectively.
Putaminoxin, a phytotoxic nonenolide from Phoma putaminum
Phoma putaminum, the causal agent of leaf necrosis of Erigeron annuus, a common weed of field and pasture, produced toxic metabolites when grown in liquid culture. The main phytotoxin, named putaminoxin, was isolated and characterized using spectroscopic and chemical methods as (5S)5-hydroxy-9-propyl-6-nonen-9-olide, a new 10-macrolide. When assayed on leaves of host and non-host plants, putaminoxin showed a wide range of toxicity, with leaves of E. annuus being most sensitive.