Phenolic Acids in Some Cereal Grains and Their Inhibitory Effect on Starch Liquefaction and Saccharification
详细信息 查看全文
- 作者：Amin Kandil ; Jihong Li ; Thava Vasanthan ; David C. Bressler
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：August 29, 2012
- 年：2012
- 卷：60
- 期：34
- 页码：8444-8449
- 全文大小：225K
- 年卷期：v.60,no.34(August 29, 2012)
- ISSN：1520-5118
文摘
The presence of phenolic acids in cereal grain is thought to influence starch hydrolysis during liquefaction and saccharification of grain flours in the bioethanol industry. As a basis for remodeling starch hydrolysis systems and understanding inhibition mechanisms, the composition and concentration of phenolic acids in whole grain flours of triticale, wheat, barley, and corn were analyzed by high-performance liquid chromatography. The total phenolic acid contents (sum of nine phenolic acids) in the four grains were 1.14, 1.70, 0.90, and 1.25 mg/g, respectively, with more than 90% found in the bound form. Ferulic, coumaric, and protocatechuic acids were the major phenolic acids in triticale and wheat. Gallic acid was also rich in triticale. Ferulic, coumaric, hydroxybenzoic, and gallic acids were predominant in barley. In corn, ferulic, coumaric, gallic, and syringic acids were abundant. On the basis of these profiles, pure phenolic acids were added individually and collectively to isolated starches at amounts either equivalent to or 3 times those in the whole grains for hydrolysis. The degree of starch hydrolysis with 伪-amylase and amyloglucosidase decreased up to 8% when individual phenolic acids were present in cooked starch slurry. The decreases were more pronounced when phenolic acids were added collectively (4鈥?% with 伪-amylase and 9鈥?3% with sequential 伪-amylase and amyloglucosidase). The study of a phenolic acid鈥搒tarch鈥揺nzyme model system indicated that the interactions of phenolic acid鈥揺nzyme and phenolic acid鈥搒tarch significantly contributed to the inhibitory effect of starch hydrolysis. Heating facilitated the interactions. Phenolic acids thus play a significant role in the resistance of starch to enzyme and/or the loss of enzyme activity during starch hydrolysis.