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Several plant extracts are being investigated to produce edible coatings, mainly due to their antioxidant and antimicrobial activities. In this study, licorice root extracts were produced by ultrasound‐assisted extraction and were combined with chitosan to elaborate edible coatings. Different solvents and temperatures were used in the extraction process, and the antioxidant and antimicrobial activity of the extracts were assessed. The most bioactive extracts were selected for the development of the edible coatings. The rheological properties of the coatings were studied, and they were applied on strawberry to evaluate their physicochemical and microbiological properties. The addition of licorice extract to chitosan resulted in positive effects on the rheological properties of the coatings: the incorporation of phytochemicals to chitosan decreased the shear stress and improved the restructuring ability of the coating solutions. The films presented a reduction of the Burger model parameter, indicating a reduction of rigidity. Furthermore, the strawberry coated with chitosan and licorice extract maintained good quality parameters during storage and showed the best microbiological preservation in comparison with controls. Hence, the use of chitosan with licorice extract is a potential strategy to produce edible coating for improving the postharvest quality of fruits, This research was funded by Comunidad Autónoma de Madrid, grant number P2013/ABI27, project Bolívar Gana con Ciencia, MinCiencias Contract 368-2019 and Programa Nacional de Innovación Agraria—PNIA of Perú, Contract: No. 152-2018-INIA-PNIA-PASANTIA

Stabilizers are ingredients employed to improve the technological properties of products. The food industry and consumers have recently become interested in the development of natural ingredients. In this work, the effects of hydrocolloids from butternut squash (Cucurbita&nbsp, moschata) seeds (HBSS) as stabilizers on the physicochemical, rheological, and sensory properties of natural yogurt were examined. HBSS improved the yogurt’s physical stability and physicochemical properties, decreasing syneresis and modifying the samples’ rheological properties, improving the assessment of sensory characteristics. The samples presented shear thinning behavior characterized by a decrease in viscosity with the increase of the shear rate, nevertheless, the samples showed a two-step yield stress. HBSS is an alternative as a natural stabilizer for the development of microstructured products.

The use of flour from shrimp (Penaeus vannamei) heads with a high content of protein (SHF) to stabilize food emulsions type oil in water (o/w) is an alternative to take advantage of the by-products of the shrimp industry. The aim of this work was to prepare food emulsion type oil in water (o/w) using the SHF due to the high percentage in proteins; for this procedure a physicochemical and bromatological characterization of flour of shrimps (Penaeus vannamei) heads has been done, in which a percentage of protein 51 %, moisture of 11,82 %, fat 8,52 % and 22,23 % of ash has been obtained. The base emulsions may be used in food products such as salad dressing, mayonnaise, spreads, dressings and other products. The different emulsions with adequate rheological and microstructural characteristics were prepared using different concentrations of palm oil (20, 30 and 40%w/w) and different concentrate of SHF (0,5, 1 and 2 % w/w). Therefore, we have obtained a food emulsion stable type oil in water (O/W) with 2 % w/w of SHF, which presented a behavior non-Newtonian fluid type shear-thinning and homogeneous distribution of droplets. El uso de harinas obtenidas a partir de las cabezas de camarones (Penaeus vannamei) - SHF con un altos contenido en proteína para la estabilización de emulsiones alimentarias del tipo de aceite en agua (O/W) son una alternativa para poder aprovechar estos residuos de la industria del camarón. El objetivo de este trabajo fue preparar emulsiones alimentarias aceite en agua (O/W), utilizando la SHF, debido a su alto porcentaje de proteínas. Se realizó la caracterización fisicoquímica y bromatological de la harina SHF, obteniendo unos porcentajes del 51 % en proteína, 11,82 % de humedad, 8,52 % de grasa y 22,23 % de ceniza. Las emulsiones logradas pueden ser utilizadas en productos alimenticios tales como ensaladas, mayonesa, productos para untar, aderezos, entre otros. Se prepararon emulsiones bases con diferentes concentraciones de aceite de palma (20, 30 y 40 % w/w) y de SHF (0,5, 1 y 2 % w/w). A las diferentes emulsiones que presentaron estabilidad se les realizaron las caracterizaciones reológicas y microestructural. Por lo tanto, se obtuvieron emulsiones estables del tipo aceite en agua (O/W) con 2 % w/w de SHF que presenta un comportamiento no newtoniano del tipo reofluidificante y la distribución homogénea de gotitas.

The tropical fruits are sensitive to low storage temperatures, so optimal parameters have been searched for storage and transport for the purpose of maintaining its overall quality as long as possible to the consumer. The effect of different storage temperatures (6, 10, 15, 21 and 27 °C) and storage durations (0 to 20 d) on total phenolics and enzymatic activity of peroxidase (POD), catalase (CAT), and polyphenol oxidase (PPO) on sapodilla (Achras sapota L.) fruit was investigated. The extraction and quantitation of protein and phenols from fruit was performed, then the enzymatic activity of PPO, POD and CAT was determined. The concentration of total phenolics decreased in the control fruit. POD activity was 3268.7 ± 1.4 U g-1 in ripening and senescence of sapodilla stored at 27 °C. CAT activity reached a peak of 34.0 ± 0.25 U g-1 in senescence in control fruit. PPO activity remained unchanged in the ripening stage and until consumption. The best storage temperatures to prolong the post-harvest life of the sapodilla fruit were 6 °C and 10 °C when storage was at low temperatures. POD activity was inactivated during sapodilla storage at low temperatures (6 and 10 °C) and after being transferred to 27 °C the activity was reactivated. Likewise of fruits stored at 21 °C after being transferred to 27 °C the POD activity was reactive with a maximum value of 46.3 ± 0.012 U g-1. Enzyme activity decreased at low temperatures, which contributed to the preservation of the fruit, showing that the cold retards the maturation processes.

In this study, food emulsions of oil in water from sesame (Sesamum indicum) protein isolates and their oil were formulated and standardised. The effect of the concentrations of sesame (Sesamum indicum) protein isolates and base oil and the speed of the emulsification process for the food emulsion stability was studied. The protein isolates were achieved from the defatted sesame flour (DSF), obtaining a percentage of 80% ± 0.05% of protein. Emulsions were formulated through a factorial design 23. The rheological behaviour of sesame (Sesamum indicum) protein isolates-stabilised emulsions and microstructural composition were investigated. Stable emulsions with suitable rheological properties and microstructure were formulated at a concentration of 10% sesame oil and different concentrations of protein isolates, between 1.5% and 2.5%, with the best droplet distribution characteristics being shown for the 2.5% sesame protein isolates. The emulsions showed a non-Newtonian fluid behaviour, adjusting the Sisko model.