Lía N. Gerschenson

Effect of natamycin, nisin and glycerol on the physicochemical properties, roughness and hydrophobicity of tapioca starch edible films

In this paper, films based on tapioca starch and containing nisin, natamycin and glycerol were characterized in relation to their physicochemical properties, roughness and hydrophobicity. The content of glycerol affected the mechanical properties of the films studied and the roughness and it was observed an increase in WVP with the increase in glycerol content. The addition of antimicrobials affected the mechanical properties, being nisin the one that produced the greater decrease in the Young modulus. The color was highly affected by the joint presence of natamycin and nisin, which increased the yellow index. The contact angle increased with antimicrobial addition indicating a decrease in hydrophilicity. Nisin also affected the roughness of the films. Water vapor permeability was slightly reduced by the presence of natamycin. It was observed that water vapor permeability and contact angle were correlated with the roughness of the films.

Conventional macroscopic pretreatment

The recuperation of valuable compounds from food wastes involves initially a stage of macroscopic pretreatment for the appropriate modification of the material to a form that is adequate for the following stages. Thermal or vacuum concentration, freeze drying, reduction of particle size, centrifugation, mechanical pressing, and microfiltration are operations that may be used for conventional macroscopic pretreatment. In the present chapter, these operations are summarized and particular examples are discussed with a final purpose of facilitating the addition of value to food wastes and to contribute to the sustainability of agro-industrial processes.

Chapter 6 – Conventional extraction

Traditional extraction technologies, such as solvent extraction and steam distillation, have been used for the recovery of natural extracts from plant and animal sources for a long time. These extracts have mainly been used as food additives and medicines. Later, other more efficient and environmentally friendly methods like enzyme-, ultrasound-, and microwave-assisted extraction, and supercritical fluid extraction were developed. Following the tendency of modern society to decrease pollution, recovery of bioactive compounds from food wastes is an alternative option that adds value to such residues and at the same time decreases their environmental footprint. In this chapter, the use of well-established extraction technologies to recover bioactive compounds from food industry wastes is presented.

Plum (Prunus salicina) peel and pulp microparticles as natural antioxidant additives in breast chicken patties

Fiber microparticles (MPCs) separately obtained from peel and pulp of Japanese plum residues contained co-extracted β-carotene, lutein, and α- and γ-tocopherols, as well as polyphenols (cyanidins, quercetin derivatives, pentameric proanthocyanidins). Peel and pulp MPCs were then separately evaluated as natural antioxidant additives (2.0% w/w level) in raw breast chicken patty, susceptible to oxidation. Their effect on technological properties was also analyzed. MPCs reduced in 50% the formation of thiobarbituric acid reactive substances (TBARS) in raw patties during 10-days storage at 4.0°C. Ferric reducing power (FRAP) was 77-157% higher in MPCs-added patties, especially with peel MPCs, being then attributed to the antioxidants supplied by these MPCs. It can be also associated to the highest α- and γ-tocopherol levels found in the peel MPCs-added patties, which remained high after cooking as well. Also, higher pectin and low lignin contents of pulp MPCs determined greater hydration, stabilized the cyanidins and, hence, the red color transferred to raw patties, and increased springiness of cooked patties. Plum peel and pulp MPCs are efficient additives for chicken meat products.