Title
Effects of extraction conditions on improving the yield and quality of an anthocyanin-rich purple corn (Zea mays L.) color extract
Date Issued
01 September 2007
Access level
metadata only access
Resource Type
journal article
Author(s)
The Ohio State University
Abstract
Purple corn (Zea mays L.) is a rich and economic source of anthocyanin colorants and functional ingredients. However, high levels of anthocyanin-rich waste are generated during processing, reducing the yields and increasing the costs of the final product. This waste has been associated with anthocyanin complexation with tannins and proteins. Our objective was to evaluate anthocyanin extraction methods to reduce purple corn waste. Different solvents (water, 0.01%-HCl-acidified water, and 0.01%-HCl-acidified ethanol), temperatures (room temperature, 50, 75, and 100 °C), and times of exposure to the solvents were investigated. Acetone (70% acetone in water) extraction was used as control. Anthocyanins, total phenolics, tannins, and proteins in extracts were measured by the pH differential, Folin-Ciocalteu, protein precipitation, and BCA assay methods. Qualitative analyses were done by HPLC coupled to a PDA detector and SDS-PAGE analysis. Water at 50 °C achieved the highest yield of anthocyanins (0.94 ± 0.03 g per 100 g dry corncob) with relatively low tannins and proteins, comparable to the anthocyanin yield obtained by 70% acetone (0.98 ± 0.08 g per 100 g dry corncob). Extending the extraction time from 20 to 60 min and using consecutive reextraction procedures reduced anthocyanin purity, increasing the yields of other phenolics. A neutral protease was applied to the extracts and effectively decomposed the major protein that was believed to contribute to the development of anthocyanin complexation and waste generation. Extraction time, consecutive reextraction procedures, and enzyme hydrolysis should be considered for high yield of anthocyanins and waste reduction. © 2007 Institute of Food Technologists.
Volume
72
Issue
7
Language
English
OCDE Knowledge area
Protección y nutrición de las plantas Nutrición, Dietética
Scopus EID
2-s2.0-34548493675
PubMed ID
Source
Journal of Food Science
ISSN of the container
00221147
Sources of information: Directorio de Producción Científica Scopus