No abstract

The olive growing is one of the strategic sectors of the Algerian economy. Traditional olive culture located in the mountains of Kabylia offers typical oil widely preferred by a large part of the Algerian consumers. However, this ancestral culture risks not only abandonment but suffers much more from uncontrolled of the good practices surrounding this local product requiring a valorization accompanied by improvement. Indeed, the difficulty to extract the total oil contained in the fruit is one of the main obstacles of the extraction method particularly by pressure. Nevertheless, some actions as the addition of co-adjuvant during the malaxing process allow improving efficiency of the extraction process. Our results indicate that the addition of 2.5% of talc as a co-adjuvant to a moistless paste obtained from whole olives significantly improves the oil yield by about 4.4% without altering the acidity compared to the control. Similarly, stoning improves the moisture of the pressed mass although without improving yield of the oil characterized by a slight decrease in acidity compared to other extracted oils. Therefore, our results confirm the beneficial effect of talc on the extraction of olive oil and contribute to the improvement of the traditional extraction by pressure to enhance the value of this local product.

This study highlighted the pro-oxidative functions of α-tocopherol (αT) on the heart antioxidant system and tissue histopathology of oxidized sunflower oil (OSO)-exposed rats.Four groups of male Wistar rats were fed with different diets: 1) control diet containing FSO (fresh sunflower oil); 2) diet containing 5 % OSO; 3) diet containing 5 % OSO, supplemented with 600 mg αT kg-1; and 4) diet containing 5 % OSO, supplemented with 1200 mg αT kg-1. The hearts were then isolated, and the antioxidant enzymatic activities were assessed. Body weight and catalase (CAT), glutathione peroxidase (GPx) activities significantly decreased in groups fed with OSO, while the lipid peroxidation (LPO) level significantly increased. Administration of OSO with αT (600 mg · kg-1) returned the body weight values and LPO levels to similar values as the control group. The CAT and GPx activities increased but remained significantly lower compared to the control group. In the OSO group with αT (1200 mg · kg-1), the CAT and GPx activities also decreased, while LPO significantly increased. Heart tissue sections obtained from the groups revealed the presence of large areas of necrosis. This study suggested that OSO induced oxidative stress and that administration of a moderate dose of αT restored the antioxidant balance, but that high levels of αT supplementation result in a pro-oxidant effect.

AbstractVegetable drying is an energy consuming procedure despite the fact that it is the most efficient way to preserve agricultural products. This study investigates a new way to dry good quality garlic at lower cost. Thin garlic layer was submitted to free convection airflow at air drying temperature of 40 °C, 50 °C, and 60 °C. Using the slope method, effective diffusivity coefficient was determined at each drying temperature during the first and second falling drying rate periods. Considering the former, it increased with increasing temperature. In relation to latter, it decreased with the temperature increase. However, at low drying temperatures, process keeps on going to very low moisture content; and it develops to an asymptotic value at high temperatures, indicating that shrinking at high temperature prevents evaporation of some residual moisture. Considered separately, these temperatures do not reflect the conditions met in solar drying, since in solar systems, air temperature increases during the day with increasing solar radiation. Therefore, characterization of garlic drying by means of step temperature varying – the first hour of drying at 40 °C; the second hour of drying at 50 °C, and the remaining time of drying at 60 °C – might better correspond with conditions under solar drying and result in better understanding of the process.