Organically grown indigenous Philippine rice: nutritional quality and aldose reductase inhibitory activity of its phenolic compounds

Date

4-2008

Degree

Bachelor of Science in Agricultural Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Maxima E. Flavier

Abstract

SERRANO, MAHALIA ADELINA CORAZON P. University of the Philippines Los Bafios , April 2008. Organically Grown Indigenous Philippine Rice: Nutritional Quality and Aldose Reductase Inhibitory Activity of Its Phenolic Compounds.

Adviser: Dr. Maxima E. Flavier

The nutritional quality of three certified organic rice — RV-8 (non-pigmented rice), M-9 (red rice), and black rice — was assessed in terms of their crude fat, crude fiber, crude protein, carbohydrates and mineral contents. The parameters were determined for both the samples with bran ("brown" rice), and without bran (milled rice). Significantly higher fat, fiber, and mineral contents were obtained for the brown rice samples compared with their milled rice counterparts, suggesting the nutritional importance of the bran. Protein content was not significantly different between the brown and milled samples. The samples were found to be high in carbohydrates, mainly in the form of starch rather than soluble simple sugars. Arnylose content (AC) was assayed to predict cooked rice texture and acceptability. Based on their amylose content, black rice. RV-8, and M-9 were classified as low AC type, intermediate AC type, and high AC type, respectively. AC was found to be very strongly and positively correlated with difficulty in chewing (r = 0.8748), and grittiness (r = 0.9795), and negatively correlated with general acceptability (r = -0.8972).

Phenolic compounds were extracted using I% HCl/methanol. Total phenolic content, determined using the Folin-Ciocalteau method, was highest for M-9 (4100 ± 95 mg Catechin Equivalent/kg sample), followed by black rice (2674 ± 75mg CE/kg), and the non-pigmented RV-8 variety (1103 ± 13 mg CE/kg). The total phenolic content decreased significantly upon removal of the bran. The major phenolic compounds present were identified as pelargonidin-3-glucoside for M-9, and cyanidin —3,5- diglucoside for black rice.

The levels of aldose reductase inhibition of the rice extracts were assayed to determine their potential in preventing diabetic complications. Among the three rice extracts, RV-8 showed the greatest inhibitory activity (43.1% inhibition at II ppm concentration), followed by M-9 (40.2% inhibition at 41ppm), and black rice (20.2% inhibition at 27ppm).

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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