Olive Oil Cake Research Articles

Lipase production by solid state fermentation of olive cake and sugar cane bagasse

Olive oil cake (OOC) from Morocco and sugar cane bagasse (SCB) were used for lipase production using thermostable fungal cultures of Rhizomucor pusillus and Rhizopus rhizopodiformis. The maximum production of lipase by Rhizomucor pusillus and Rhizopus rhizopodiformis in solid state fermentation (SSF) using SCB, was 4.99 U/g DM equivalent to 1.73 U/ml and 2.67 U/g DM equivalent to 0.97 U/ml, respectively. However, the mixture of OOC and SCB, 50% each, increased the lipase activity as high as 79.6 U/g DM equivalent to 43.04 U/ml and 20.24 U/g DM equivalent to 10.83 U/ml obtained by Rhizopus rhizopodiformis and Rhizomucor pusillus, respectively. These data compare favourably with most of the activities reported for other lipase hyperproducing microorganisms.

Prediction of the energy value of rabbit feeds varying widely in fibre content

Digestibility trials of 23 pelleted diets, with one or two ingredients and having 8.7–53.5% acid detergent fibre (ADF) on a dry matter (DM) basis, were carried out in adult rabbits fed ad libitum. Using a step-wise linear regression approach, the relationship between the digestible energy content (DE) or the coefficient of digestibility of gross energy (dGE) and the chemical composition of diets was established. Excluding beet pulp, with a very high crude fibre digestibility (54.8%), the prediction equations obtained were: DE (MJ kg −1 DM) = 14.2 − 0.205 ADF + 0.218 EE + 0.057 CP ( R 2 = 0.965, RSD = 0.494) and dGE (%) = 83.2 − 1.07 ADF ( R 2 = 0.951, RSD = 3.15) where ADF, ether extract (EE) and crude protein (CP) are expressed as a percentage on a DM basis. When diets with level of EE or CP higher than 6% or 18% respectively (grape marc, olive oil cake, brewer's grains, sunflower meal) were also removed, the prediction equations became: DE = 15.9 − 0.219 ADF ( R 2 = 0.974, RSD = 0.391) and dGE = 85.6 − 1.20 ADF ( R 2 = 0.977, RSD = 2.02). The contents in DE, digestible crude protein and undigestible crude fibre of 21 ingredients are presented and discussed in comparison with other studies.

Effect of olive oil cake on water holding capacity of sandy soils in Libya

The effect of adding olive oil cake to two sandy soils on their abilities to retain water was investigated under controlled conditions. Olive oil cake was applied to the soils in pots and rates equivalent to 0, 5, 10, and 20% by weigh of the air-dried soil. Pots were incubated for 3 weeks at controlled conditions. The results show that the addition of oil cake significantly increased (P ⩽ 0·05) the ability of the two sandy soils studied to retain water under all applied tensions. However, treatments with highest percentage of oil cake applied, had significantly higher water retention compared to those which had less. In terms of available water, which was calculated as the difference in volumetric water content between field capacity (-33 KPa) and wilting point (1·5 MPa), the highest olive oil cake applied doubled this difference in comparison to the control. An effect of soil texture was also noted. Generally, the influence of olive oil cake on the available moisture percentage was more pronounced in sand than the sandy loam.