Determination of Lutein from Fruit and Vegetables Through an Alkaline Hydrolysis Extraction Method and HPLC Analysis.

A simple and rapid analytical method for the determination of lutein content, successfully used for cereal matrices, was evaluated in fruit and vegetables. The method involved the determination of lutein after an alkaline hydrolysis of the sample matrix, followed by extraction with solvents and analysis by normal phase HPLC. The optimized method was simple, precise, and accurate and it was characterized by few steps that could prevent loss of lutein and its degradation. The optimized method was used to evaluate the lutein amounts in several fruit and vegetables. Rich sources of lutein were confirmed to be green vegetables such as parsley, spinach, chicory, chard, broccoli, courgette, and peas, even if in a range of variability. Taking into account the suggested reference values these vegetables can be stated as good sources of lutein.

Degradation of carotenoids in apricot (Prunus armeniaca L.) during drying process.

Carotenoids are natural compounds whose nutritional importance comes from the provitamin A activity of some of them and their protection against several serious human disorders. The degradation of carotenoids was investigated during apricot drying by microwave and convective hot-air at 60 and 70 °C. Seven carotenoids were identified: antheraxanthin, lutein, zeaxanthin, ß-cryptoxanthin, 13-cis-ß-carotene, all-trans-ß-carotene and 9-cis-ß-carotene; among these, all-trans-ß-carotene was found to be about 50 % of total carotenoids. First-order kinetic models were found to better describe all-trans-ß-carotene reduction during drying, with a degradation rate constant (k1) that increased two folds when temperatures increased by 10 °C, in both methods. No differences were found in k1 between apricots dried by hot air at 70 °C (k1 = 0.0340 h(-1)) and by microwave at 60 °C. The evolution of total carotenoids (117.1 mg/kg on dry basis) during drying highlighted a wider decrease (about 50%) when microwave heating was employed, for both set temperatures. Antheraxantin was found to be the carotenoid most susceptible to heat, disappearing at 6 h during both trials with microwave as well as during convective hot-air at 70 °C. For this reason, antheraxanthin could be a useful marker for the evaluation of thermal damage due to the drying process. Also the degree of isomerization of all-trans-ß-carotene could be a useful marker for the evaluation of the drying process.

An innovative pre-ripening drying method to improve the quality of pasta filata cheeses.

In order to optimise the pre-ripening of pasta filata cheeses, two traditional Italian cheeses, Caciocavallo and Scamorza, were dried for different times at 15 °C, 50% relative humidity and airflow rate of 1000 m3/h, by using a pre-ripening plant. During ripening, microbiological, chemical-physical and sensorial analyses were applied to the products in order to evaluate the impact of the innovative pre-ripening technique used on the cheese characteristics. The used plant led to commercial time saving and to the standardisation of the process, making it unaffected by the effects of temperature and humidity variations, common in small industries. The final products showed good chemical-physical and sensorial qualities and resulted in a higher microbiological safety, preserving their traditional characteristics.