OHMIC HEATING-ASSISTED EXTRACTION OF ANTHOCYANINS FROM BLACK RICE BRAN TO PREPARE A NATURAL FOOD COLOURANT

ABSTRACT Black glutinous rice bran (Oryza sativa L.) is a potential source of the dark purple anthocyanin pigments. This study investigated some quality aspects and bioactive compounds of the colourant powder obtained from rice bran extracted by ohmic heating (OHM) assisted solvent extraction. The moisture content (MC) of the bran sample investigated was adjusted to 30% and 40%. Four different levels of electric field strengths (E) of 50, 100, 150, and 200 V cm– 1 were applied. The results showed that OHM assisted solvent extraction was a promising method offering both high yield and high concentration of bioactive compounds. The solubility, aw, bulk density, and color values (L*, C*, and h°) of the colorant powder of all treatments were comparable. The colourant powder obtained from the bran extracted using OHM with 30% MC (E=100, 150, and 200 V cm– 1) and 40% MC (E = 50, 100, 150, and  V cm– 1) had the highest level of bioactive compounds.
  TABLE OF CONTENTS ABSTRACTii LIST OF TABLESiv LIST OF FIGURESvi CHAPTER ONE1 INTRODUCTION1 1.2Black Rice Bran3 1.3.1   History6 1.3.2   Principle of Operation7 1.3.3    Advantages9 1.3.4   Disadvantages10 1.3.5   Flow chart and Key Equipment.11 1.3.6    Equipment design11 1.3.6   Major challenges and needs for future research and development13 CHAPTER TWO17 MATERIALS AND METHODS18 2.6.1.   Preparation of sample extract.22 2.8.1   Solubility24 2.8.3   Bulk Density25 CHAPTER THREE26 RESULTS AND DISCUSSIONS26 CHAPTER 443 CONCLUSIONS43 REFERENCES44