Influence of air temperature on drying kinetics and antioxidant potential of olive pomace

This work aims to evaluate the influence of olive pomace drying (a solid by-product of the olive oil industry) on both antioxidant potential and drying kinetics. The two main fractions of olive pomace (pits, PI and pulps + peels, P + P) were characterized by image analysis and density measurement. The drying process was analyzed in experiments carried out at different temperatures (from 50 to 150 °C) and mathematically described from the diffusion and Weibull models. The antioxidant potential of the extracts (ethanol–water 80:20 v/v, 22 ± 1 °C, 170 rpm for 24 h) obtained from the dry product was analyzed by measuring the total phenolic content and antioxidant capacity and the main polyphenols were quantified by HPLC–DAD/MS–MS.     

Preliminary study of the production of apple pomace and quince jelly

Apple pomace, a cheap by-product of apple juice and cider production, is rich in pectins and flavour compounds. Thus, a possible way of valorization of apple pomace was using it for jelly production. Fresh apple pomace from Braeburn, Gala, Golden Delicious and Granny Smith was used for the preparation of jelly to study the amount of sugar and quince content and the cooking time effect. The response surface methodology was used to study the preparation of apple pomace jelly and responses studied were textural characteristics and overall acceptability. The hardness of jelly was not affected by the factors studied whereas cohesiveness and overall acceptability were affected by the concentration of quince and sugar. The most appreciated jellies were those prepared with the highest quince concentration and the lowest sugar concentration.     

利用苹果渣制备膳食纤维的工艺研究

以苹果渣为原料，利用单因素实验和正交实验研究了可溶性膳食纤维和不溶性膳食纤维的提取工艺。本文是前一部分制备可溶性膳食纤维的实验。结果表明：提取可溶性膳食纤维A的最佳工艺条件是粒度40目，0．3％盐酸溶液，液料比15：1（ml/g) ,温度80℃时，反应2.0h；可溶性膳食纤维B的最佳工艺条件是8％NaOH溶液，液料比8：1（ml/g)，温度90℃时，反应3.0h。     

苹果渣中多酚物质的纯化及其抑菌活性的研究

本实验运用静态吸附与解吸实验对10种大孔树脂进行筛选,筛选出效果最好的树脂对苹果渣中多酚物质进行动态吸附实验研究,并采用滤纸片法研究了多酚纯化物的抑菌活性及其质量浓度、pH值、温度对抑菌活性的影响。结果表明:D4020大孔树脂表现出良好的吸附性能与最好的解吸效果;苹果渣多酚纯化物对细菌的抑制作用较强,而对供试霉菌、酵母菌抑制作用不明显,其对大肠杆菌和金黄色葡萄球菌的最低抑制浓度(MIC)均为0.015%(W/W);在pH5～6环境条件下其抑菌效果最佳;一定温度内处理不影响苹果多酚的抑菌活性。     

Relative effects of cultivar, heat-treatment and sucrose content on the sensory properties of blackcurrant juice

The effects of processing treatments (heat, sucrose addition) on the sensory quality of blackcurrant juices prepared from two genetically diverse cultivars (Ben Lomond and Ben Alder) were examined using sensory profiling. Sucrose level had the largest effect on the sensory profile, with heating and cultivar having smaller but still significant effects. Some interaction between sucrose level and heating of the juices was observed in the sensory profile. The results indicate that selection of preferred genotypes remains an important breeding objective in blackcurrant improvement programmes, since the sensory attributes associated with genotype persist, despite processing effects, in the extracted juice.     

Biosorption of protons and heavy metals onto olive pomace: modelling of competition effects

Heavy metal biosorption onto solid wastes from olive oil production plants, olive pomace, has been investigated. Acid-base properties of the active sites of olive pomace were determined by potentiometric titrations and represented by a continuous model accounting for two main kinds of active sites. Competition among protons and heavy metals in solution was considered by performing biosorption tests at different equilibrium pH with single (Cu and Cd) and binary metal systems (Cu-Cd). Both Langmuir extensions and non-ideal competitive adsorption models (NICA models) can be used to represent experimental data of Cu and Cd biosorption in single metal systems at different equilibrium pH. Nevertheless only NICA models, accounting for site heterogeneity and non-ideal adsorption of the different species simultaneously present in solution, can adequately simulate the competition among Cu and Cd in binary metal systems by using the parameters fitted to single system data.