Banca de QUALIFICAÇÃO: RAPHAEL LUCAS JACINTO ALMEIDA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : RAPHAEL LUCAS JACINTO ALMEIDA
DATE: 15/07/2022
TIME: 09:00
LOCAL: Via Google Meet
TITLE:

PRODUCTION OF RED RICE STARCH NANOCRYSTALS USING HYDROTHERMAL AND ENZYMATIC PRE-TREATMENTS FOR STABILIZATION OF PICKERING EMULSION

KEY WORDS:

Modified starch, Non-thermal pre-treatment, In vitro digestibility, Starch nanocrystals, Emulsion stabilization.

PAGES: 192
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Bioquímicos
SUMMARY:

Hydrothermal pretreatments combined with enzymatic modification could be a promising alternative to break down starch granules and/or create pores and cracks and thus allow better acid diffusion during the production of starch nanocrystals. These nanocrystals can be used to increase the stability of the Pickering emulsion, which are defined as emulsions stabilized with solids, which has been showing interest from the scientific community as an interesting alternative due to the double wettability of the particles, which avoids the application of surfactants. Thus, the present study evaluated the use of hydrothermal and enzymatic pre-treatments on red rice starch for the production of nanocrystals for the application and stabilization of Pickering emulsions. For this, non-thermal pretreatment with pulsed electric field (PEF: 10 and 30 kV cm-1) was used on starch and hydrothermal (HPT: autoclave and cooking) on grains and starch, where the latter was combined with enzymatic hydrolysis using α-amylase. It is also noteworthy that a new strategy was used for hydrolysis, called semi-simultaneous (HSS), aiming to optimize the process time, reduce the amount of solvents, when compared to the consecutive form (CH) with α-amylase and amyloglucosidase, both with an enzymatic load of 9 U mg-1. After the enzymatic modification, the modified starches were characterized in terms of their technological properties and in the case of CH and HSS modification, the glycemic index was calculated. It should be noted that both with the use of PEF and HPT there was a decrease in the drying time of red rice starch, being the temperature of 50ºC chosen, due to the feasibility of execution and with extraction yield using HPT being higher. HPT when applied to starch was viable to modify the structure and enzymatic susceptibility of red rice starch and combined with the action of α-amylase modified the starch creating favorable conditions for the diffusion of the acid during the production of nanocrystals. It is also noteworthy that the HSS method was more effective, presenting a higher value of digestion degree and optimized technological properties in relation to native starch, as a suggestion new models can be used to adjust the enzymatic kinetics. In this sense, the combination of HPT with enzymatic modification with both α-amylase and α-amylase and amyloglucosidase were viable for the production of modified starch and later for the production of starch nanocrystals.

COMMITTEE MEMBERS:
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Interna - 3214434 - NATHALIA SARAIVA RIOS
Externo ao Programa - 027.194.253-38 - SÉRGIO DANTAS DE OLIVEIRA JÚNIOR