Banca de DEFESA: ANDRÉ LEONARDO DOS SANTOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANDRÉ LEONARDO DOS SANTOS
DATE: 20/12/2024
TIME: 09:00
LOCAL: Acesso remoto
TITLE:

Study of the physical and technological properties of Sorghum bicolor (L.) Moench and pearl millet (Pennisetum glaucum (L.) R. Br.) bran and the use of thermoplastic extrusion as pretreatment for supercritical extraction of bioactive compounds

KEY WORDS:

Bran, Starch, Paste Properties, Millet, Decortification

PAGES: 117
BIG AREA: Ciências Agrárias
AREA: Ciência e Tecnologia de Alimentos
SUBÁREA: Tecnologia de Alimentos
SPECIALTY: Tecnologia de Produtos de Origem Vegetal
SUMMARY:

The bioactive compounds found in grains have attracted the interest of the food and pharmaceutical industries. These compounds are mostly present in whole grains and, particularly, in the bran fraction (pericarp). Pearl millet and sorghum are grains with bioactive potential. The most cultivated species of millet in the world is Pennisetum glaucum (L.) R. Br., being the sixth most produced cereal. Millet grains have excellent nutritional quality and are comparable or superior to some frequently consumed cereals, such as rice and wheat. Sorghum (Sorghum bicolor (L.) Moench) is among the five most important cereals in the world, being a source of phytochemical compounds, such as phenols, anthocyanins, tannins, flavonoids and antioxidants. The extraction of these compounds must be done with maximum efficiency, requiring advanced pretreatment and extraction techniques, preferably using green solvents. Thermoplastic extrusion (TE) is a versatile process used as pretreatment for the release of compounds of interest. Supercritical fluid extraction (SFE) is used to extract bioactive compounds from different sources. The literature does not report studies in which thermoplastic extrusion is used as pretreatment for SFE in sorghum and pearl millet brans. These two techniques were used in this study to evaluate the pretreatment process and supercritical extraction in obtaining bioactive compounds from pearl millet and sorghum brans so that the obtained fractions are concentrated in bioactive compounds of interest. The pearl millet grains debranning for 25 minutes showed the highest bran percentages (15.5%) and (30.7%). The branning time influenced the starch content. The highest final viscosity was millet bran (MB) 80.0 cP. Bran recovery was positively correlated with total starch (0.96). Principal component analysis (PCA) showed that MB25 was associated with total starch. HCPC analysis formed two main groups: MB25 and MB05-MB10 as cluster 1, and SB10 and SB05-SB07 as cluster 2. The highest total phenolic compounds (TPC) content was 1240.94 μg GAE / 100 g in extruded pearl millet bran (MEB), and the highest antioxidant capacity (AC) was 55.51 μmol TE / g in extruded sorghum bran (SEB). Pearson correlation indicated strong positive relationships between TPC, AC-ABTS and SV. The extruded samples showed higher homogeneity and apparent density (29.72 % ), but lower porosity.Colorimetric analysis revealed a ΔE* of 8.49 for EMB and 9.78 for ESB. SFE showed that the highest TPC concentration was 21.34 mg GAE / g extract, obtained at 40 °C 10 MPa and 15% co-solvent. EMB showed the highest AC, in ABTS it was 4.47 µM TE / g of extract and in FRAP it was 157.92 µM TE / g of extract, obtained at 50 °C, 10 MPa and 15% co-solvent and 50 °C, 20 MPa and 0.5% co-solvent, respectively. The variables temperature (T), pressure (P) and percentage of co-solvent (C%) directly influenced the TPC and antioxidant activity (CA-ABTS/FRAP). In the kinetic study, the highest yield was 20 % for ESB, and the fraction of extract recovered in the CER step was higher in MB (79.71 %), with higher total recovery in the extruded sample. Extracts of sorghum and millet bran, rich in bioactive compounds, showed yields comparable to or higher than those of other cereals, highlighting TE and SFE technologies as sustainable and effective alternatives for bioactive extraction.

COMMITTEE MEMBERS:
Presidente - ***.412.587-** - CARLOS WANDERLEI PILER DE CARVALHO - EMBRAPA
Interno - ***.290.788-** - JOSÉ LUIS RAMIREZ ASCHERI - EMBRAPA
Interno - ***.726.462-** - OTNIEL FREITAS SILVA - EMBRAPA
Externa à Instituição - GABRIELLI NUNES CLÍMACO - UNICAMP
Externa à Instituição - MARIA EUGÊNIA ARAÚJO SILVA OLIVEIRA - UNIRIO