Milky Stage Versus Dough Stage of Immature Wheat Grain: Effects on Phytic Acid and Fructan Contents, Antioxidant Activity, Textural Parameters, and Sensory Characteristics of Set-Type Yoghurts

Abstract

Experimental design was performed by using immature wheat grain (IWG) harvested in two different maturation stages for set-type yoghurt production. IWG was harvested at milky (20 days after anthesis) and dough (30 days after anthesis) stages and was milled. Yoghurt samples were supplemented with milky stage grain flour (MSGF) and dough stage grain flour (DSGF) at 1, 2, and 3% concentrations except for control. All treatments were evaluated with respect to physicochemical, antioxidative, microbiological, textural, and sensorial aspects throughout the 28 days of storage. Phytic acid content of all samples diminished depending on increasing pH values over the storage while it was found higher in MSGF fortified yoghurts. The highest fructan content was determined in yoghurt fortified with 3% MSGF. Antioxidant activity and total phenolic content of yoghurts were improved with IWG fortification. MSGF showed higher antioxidant activity as compared to DSGF. On the other hand, DSGF addition presented better water holding capacity in comparison with MSGF. Likewise, DSGF provided higher firmness and consistency values. Firmness was enhanced with IWG supplementation by reducing syneresis except 1% MSGF added samples. The addition of IWG was found to slightly increase the growth of yoghurt bacteria. Both DSGF and MSGF had adverse effect on the sensory characteristics of yoghurts with their increasing concentrations. Based on the results of this study, to obtain better textural properties and higher antioxidant activity, IWG in different ripening stages can be tried with half combinations (total 3%) in yoghurt. Also, sensorial properties can be improved by flavoring agents. HIGHLIGHTS Yoghurts were supplemented with milky and dough stage wheat grain flours. Total antioxidant capacity was improved by wheat grain flour supplementation.  Milky stage wheat provided higher fructan content than that of dough stage wheat. Fermentation reduced phytic acid levels in yoghurts containing wheat grain flours.