Banca de DEFESA: RAPHAEL LUCAS JACINTO ALMEIDA
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : RAPHAEL LUCAS JACINTO ALMEIDA
DATE: 06/02/2024
TIME: 14:00
LOCAL: Via Google Meet
TITLE:
PRE-TREATMENTS APPLIED TO RED RICE STARCH FOR THE PRODUCTION OF NANOCRYSTALS FOR USE IN OIL/WATER (O/W) PICKERING EMULSIONS
KEY WORDS:
Pulsed electric field; Hydrothermal modification; In vitro digestibility; Food emulsion; Quercetin supplementation.
PAGES: 390
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Bioquímicos
SUMMARY:
During the production of starch nanocrystals (SNC), pre-treatments can be a promising alternative to break starch granules and/or create pores and cracks, allowing better acid diffusion. These nanocrystals can be used to enhance Pickering emulsion stability. Thus, the present study evaluated the use of non-thermal, hydrothermal, and enzymatic pre-treatments on red rice starch for SNC production. Non-thermal pre-treatment (I) with pulsed electric field (PEF: 10 and 30 kV cm-1) on starch was employed, and its action was assessed when combined with α-amylase pre-treatment (II) (PEF+α). Hydrothermal pre-treatment (III) (autoclaving and cooking) on grains and starch was examined for its influence on drying kinetics, and both were subsequently combined with enzymatic hydrolysis using α-amylase (IV). A new route of enzymatic starch modification was evaluated after HPT treatment, using the α-amylase and amyloglucosidase enzymes in a semi-simultaneous manner (HSS), in comparison with the conventional technique, which is done consecutively (CH). Semi-simultaneous hydrolysis (HSS) strategy (V) was tested to optimize process time and reduce solvent quantity compared to consecutive hydrolysis (CH) with α-amylase and amylglucosidase, both with enzyme loading of 9 U mg-1. Results showed that both PEF and HPT reduced drying time by up to 180 min, with HPT achieving the highest yields (53.54%). The order of PEF application affected starch structural characteristics, with PEF30+α being more effective in reducing syneresis and retrogradation due to an 83.30% increase in the degree of digestion. HPT applied to starch was viable for modifying structure and enzymatic susceptibility with α-amylase, resulting in changes in granule geometry, breakdown of amylose and amylopectin molecules, reduced crystallinity, and the formation of amylose-lipid complexes. The HSS method (α-amylase and amyloglucosidase) was more effective, presenting a higher degree of digestion (80.08%) and optimized technological properties compared to native starch. Autoclave-based HPT (A3) allowed efficient SNC production in just 1 day of acid hydrolysis, significantly reducing process time. When applied in Pickering emulsions, SNCs (3%) effectively stabilized temperatures at 4, 25, and 40°C, with a maximum particle size of 180 µm, reduced to 138 µm without quercetin and 98 µm with quercetin (1%) on the 21st day. Although sulfuric acid hydrolysis is the most common method for SNC production due to its low cost, there is a need to improve the process through further research, as low yield and long production times hinder progress. Exploring new routes to modify native starch is important, focusing on environmentally friendly techniques, where combined thermal and non-thermal methods offer the advantage of altering starch structure while minimizing the use of toxic reagents. These emerging methods should be applied to assess Pickering emulsion stabilization, which can be viable by enhancing interfacial interactions.
COMMITTEE MEMBERS:
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Interno - 3304882 - CARLOS EDUARDO DE ARAÚJO PADILHA
Interna - 3214434 - NATHALIA SARAIVA RIOS
Externo à Instituição - PEDRO FERREIRA DE SOUZA FILHO - UFPE
Externo à Instituição - SÉRGIO DANTAS DE OLIVEIRA JÚNIOR - INPA