Arantzazu Valdés García

Characterization and Classification of Almond Cultivars by Using Spectroscopic and Thermal Techniques

UNLABELLED Three different almond cultivars (Spanish Guara, Marcona, and Butte from U.S.A.) were characterized by using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and thermal analysis techniques (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). All samples were directly analyzed without the need of a previous oil extraction. Similar FTIR bands were observed for all studied cultivars corresponding to specific functional groups characteristics of almond ingredients (water, fat, protein, and carbohydrates). Significant differences were observed between cultivars according to absorbance and maximum wave number values of specific bands observed by FTIR and melting and crystallization parameters obtained by DSC. TGA showed that samples were stable up to around 220 °C. Different stages of degradation were observed with increasing temperature corresponding to the degradation of the complex matrix of the samples. Successful discrimination was obtained for all samples by applying multivariate stepwise linear discriminant analysis (LDA) separately to data obtained from FTIR and DSC. A satisfactory multidisciplinary approach was also performed by inserting together all parameters obtained from the 3 techniques as predictors ensuring higher reliability of the obtained model. The obtained results proved the suitability of the studied analytical techniques combined with LDA for an easy and fast discrimination among different almond cultivars in food processing. PRACTICAL APPLICATION The study of spectroscopic and thermal parameters could be used as a control tool for the direct and fast assessment of almond samples in food processing, particularly for protected designation of origin products.

Microencapsulation of Natural Antioxidant Compounds Obtained from Biomass Wastes: A Review

Growing interest in biomass valorisation in recent years has led to an increasing research focusing on its high content in phytochemicals showing high potential health benefits related to their antioxidant, anti-inflammatory and antibacterial properties, among others. On the other hand, the demand for natural antioxidants in industry is continuously increasing to avoid the harmless character of some chemical additives and, also, to limit oxidation processes in the final material, such as in food and cosmetics; increasing consumer acceptance. However, the majority of them are usually sensitive to several factors such as oxygen, light, heat, enzymes, salts, and acid or alkali mediums which lead to losses of their activity and beneficial effects. As a consequence, microencapsulation technique has been proposed in last years as a way to enhance the stability, solubility and bioavailability of these compounds. In this chapter, phytochemical compounds classification followed by their main characteristics and properties are summarized. Also, microencapsulation techniques for phytochemicals are reviewed including processes for preparing microparticles, mainly focused on spray-drying method, for industry applications.