Effect of polyphenols on mixing properties and solvent retention of wheat flour doughs.

BACKGROUND: The effect of polyphenol addition on dough mixing properties and flour functionality was examined using flours from different wheat varieties. RESULTS: Both the mixograph and farinograph experiments showed that polyphenol addition affected dough stability and optimum mixing time. These effects were most apparent in hard wheat flour with the addition of catechin. Water absorption was dependent on wheat variety (P < 0.0001) but not on the addition of polyphenols (P = 0.54). Except for the 5 g kg-1 sodium carbonate solvent retention capacity (SRC), SRC values of the flours were dependent on wheat variety but not on polyphenol addition. However, 5 g kg-1 sodium carbonate SRC was significantly increased by the addition of caffeic acid and catechin. Since sodium carbonate SRC is associated with damaged starch levels, further investigations are needed to see how polyphenols influence either the absorption of a sodium carbonate solution or the starch itself. CONCLUSION: Polyphenol addition affected dough stability and optimum mixing time. Addition of catechin to hard wheat flour was most effective. Water absorption and SRC values except for 5 g kg-1 sodium carbonate solvent were affected by the wheat variety, but not by polyphenol addition. © 2021 Society of Chemical Industry.

Rice varieties in relation to rice bread quality.

BACKGROUND: It is difficult to predict rice bread quality only from the amylose content (AC) or dough characteristics of new lines produced by rice breeding programmes. This study investigated the AC relative to bread baking quality of rice varieties developed in Korea, and identified specific characteristics that contribute to rice bread quality. RESULTS: Manmibyeo, Jinsumi, Seolgaeng and Hanareumbyeo were classified as low AC, YR24088 Acp9, Suweon517, Chenmaai and Goamibyeo as intermediate AC and Milyang261 as high AC. Suweon517, Milyang261 and Manmibyeo had a high water absorption index (WAI), while Goamibyeo, YR24088 Acp9, Jinsumi, Seolgaeng, Hanareumbyeo and Chenmaai had a low WAI. The gelatinisation enthalpy of flour varied from 9.2 J g(-1) in Milyang261 to 14.8 J g(-1) in YR24088 Acp9. After 7 days of storage the rate of flour retrogradation and crumb firmness were weakly correlated, with the exception of Jinsumi. Bread volumes of Jinsumi, Chenmaai, YR24088 Acp9 and Goamibyeo were comparable to that of wheat flour, but the rest were unsuited to bread making because of their low volume and hard crumb texture. CONCLUSION: Based on volume, texture and crumb firmness ratio, Chenmaai and Goamibyeo were the most appropriate varieties for making bread. An intermediate AC and low WAI were the primary indicators of rice bread flour quality.

Effect of phenolic acids on the rheological properties and proteins of hard wheat flour dough and bread.

BACKGROUND: The effects of different phenolic acids on the rheological properties and gluten proteins of hard wheat flour dough and bread were investigated. Caffeic, ferulic, syringic and gallic acids were each blended with hard wheat flour at a concentration of 4.44 µmol L(-1) g(-1) flour. RESULTS: Mixing time and tolerance were reduced with the addition of phenolic acids. The phenolic acids reduced the maximum resistance to extension (R(max)) and increased the extensibility of dough, with effects in the following order: gallic < syringic < ferulic < caffeic acid. The effect on R(max) was more pronounced in overmixed dough. Loaf volume was most significantly decreased with the addition of caffeic acid. Extraction of sodium dodecyl sulfate-soluble high-molecular-weight proteins was increased in both mixed and fermented doughs by the addition of ferulic and caffeic acids. The order of influence of the phenolic acids on the rheological properties and protein structure of dough and bread was consistent with that of their antioxidant activity. CONCLUSION: The addition of caffeic and ferulic acids reduced R(max) and increased the extensibility of hard wheat flour dough by modifying the high-molecular-weight gluten, which resulted in decreased bread volume.

Antioxidant activity of hard wheat flour, dough and bread prepared using various processes with the addition of different phenolic acids.

BACKGROUND: The purpose of this study was to evaluate the effect of baking process on the antioxidant activity of different phenolic acids. Antioxidant potential was determined using the ß-carotene-bleaching activity assay, and free phenolic acid levels were determined by high-performance liquid chromatography. Four phenolic acids, caffeic acid, ferulic acid, syringic acid and gallic acid, were mixed with wheat flour at a concentration of 4.44 µmol/g of flour. RESULTS: Type of phenolic acid and processing affected antioxidant activity. Of the phenolic acids, caffeic acid had the most pronounced antioxidant effect. The ranking of phenolic acids in terms of their antioxidant activity in fermented dough and bread was similar to that before processing, i.e. syringic acid < gallic acid < ferulic acid < caffeic acid. The content of ferulic acid was greater than that of the other phenolic acids after baking. Antioxidant activity and free phenolic acid content were reduced by mixing but recovered after fermentation and baking. Phenolic acid recovery after baking was 74-80%. CONCLUSION: Phenolic acids retain their antioxidant activity after the baking process, which has potential health benefits for consumers. Elucidation of interactions between the baking process and phenolic acids is important for the development of functional foods.