Determination of the diffusion coefficient through oil absorption and moisture loss, such as the porosity of pieces of yam (Dioscorea rotundata) during deep fat frying.

This study evaluated moisture loss, oil gain and porosity when frying pieces of yam (Dioscorea rotundata). The parallelepiped-shaped samples, approximately 1 × 1 × 4 cm, were subjected to frying temperatures of 145, 165 and 185 °C for 50, 150, 300, 450, or 600 s. Fick's law was used to determine the diffusion coefficient from the experiment data for the varieties 153 traditional Espino and 125 Brazilian Espino. The moisture loss in 153 traditional Espino was greater than in 125 Brazilian Espino. The diffusion coefficient and the activation energy were determined for both varieties, which were higher in the 153 traditional Espino variety. The porosity was expressed as a percentage and was also higher in the 153 traditional Espino variety.

Lipofilización del almidón de Dioscorea rotundata P. y su posible uso como agente emulsificante / Lipophilitation of dioscorea rotundata P. starch and its possible use as an emulsifying agent

Objetivo: evaluar la capacidad emulsificante de almidón nativo, hidrolizados e hidrolizados˗lipofilizados a partir del tubérculo de ñame (Dioscorea rotundata). Método: el almidón se obtuvo por el método de rayado y decantación convencionales. Se evaluó el almidón de ñame nativo, que se hidrolizó en medio ácido (40 g almidón+100 mL Agua+3.4 g HCl por 6 horas a 50 °C). Parte del almidón hidrolizado se lipofilizó a dos niveles (10 y 15 mL) mediante reacción con anhídrido dodecenil succínico (DDSA). La capacidad emulsificante se calculó mezclando 25 mL de aceite de maíz, 25 mL de agua y 1 g de almidón por triplicado con fuerte homogenización ( Ultra Turrax®), midiéndose la cantidad de material aún emulsificado luego de 24 horas. Resultados: se apreciaron variaciones de las propiedades en la comparación del almidón nativo. Los porcentajes de sustitución de los almidones, se observa fácilmente la tendencia esperada, es decir, en tanto mayor cantidad de reactivo, mayor sustitución. Se demuestra que la lipofilización del almidón incrementa su capacidad emulsificante. Conclusiones: los almidones lipofilizados con anhidro dodecenil succínico (DDSA) pueden considerarse una nueva alternativa de materia prima en la industria cosmética(AU)

Objectives: to assess the emulsifying capacity of the native starch, the hydrolyzed and hydrolyzed-lipophilyzed products from the tuber Yam (Dioscorea rotundata), Methods: the starch was obtained by the conventional method of grating and decant. Native yam starch was evaluated. It was hydrolyzed in an acid medium (40 g starch+100 mL water+3,4 g HCl for 6 hours at 50 °C). Part of the hydrolyzed starch was lipophilyzed at two levels (10 and 15 mL) through reaction with dodecenyl succinic anhydride (DDSA). The emulsifying capacity was calculated by mixing 25 mL of corn oil, 25 mL of water and 1 g of starch in triplicate with strong homogenization (Ultra Turrax®), and the amount of material still emulsified after 24 hours was then measured. Results: there were observed variations in the native starch properties. It was easy to observe the expected tendency in the substitution percentages of starches, that is, the more reagent, the more substitution. The results showed that the lipophilitation of starch increases the emulsifying capacity. Conclusions: the starches lipophilyzed with dodecenyl succinic anhydride (DDSA) are raw materials that can be considered as a new alternative in the cosmetics industry(AU)