Stale bread waste recycling as ingredient for fresh oven-baked white bread: effects on dough viscoelasticity, bread molecular organization, texture, and starch digestibility.

BACKGROUND: Wasted food produced for human consumption is estimated at 33% globally, and bread is the food product with the highest percentage. There is an ongoing drive to reincorporate food waste still useful and safe into the production chain of food for human consumption. This work aims to contribute to the study of the feasibility of recycling stale bread waste flour (BWF) into fresh oven-baked white bread, by replacing 0, 20, 40, 60, 80, and 100 g/100 g of the wheat flour with BWF. RESULTS: Storage and loss moduli increased as the BWF content increased. The baked loaf exhibited decreased lightness and yellowness but increased redness. Increasing BWF contents produced decreased loaf volume and hardness but increased moisture content. Fourier-transform infrared analysis showed that the BWF addition induced important changes in the water, protein, and starch molecular organization. Therefore, starch digestibility showed reductions in both rapidly and slowly digestible starch fractions. Principal component analysis revealed that replacements of up 20 g/100 g can produce white bread with textural, colour, and starch digestibility characteristics like that of the control bread. CONCLUSION: The fresh oven-baked white bread variation produced by replacing 20 g/100 g of the wheat flour with BWF exhibited comparable colour, volume, texture, and starch digestibility features as a control bread did made with 0 g/100 BWF. Higher replacement percentages of wheat flour by stale BWF produced unsuitable drawbacks in the white bread characteristics, but those might be deemed as convenient in other types of bakery products. © 2023 Society of Chemical Industry.

Effects of leavening agent and time on bread texture and in vitro starch digestibility.

Wheat dough added with baking dried yeast (BDY, 5 g) or baking powder (BP, 5 g) was leavened for 0, 2, 4 and 6 h for producing white bread (BBDY or BBD, respectively). The specific volume of BBDY was higher than for BBP. FTIR analysis revealed that BBP reduced the short-range crystallinity of starch granules, an effect magnified by the leavening time. Hardness and cohesiveness were higher for BBDY than for BBP which had a fragile crust structure. Readily digestible starch content of BBDY decreased (16.1-10.8%), while that of BBD increased at (17.1-31.5%) with leavening time. The opposite trend was found for resistant starch which increased from 71.2 to 79.1% for BBDY, and decreased from 69.3 to 40.2% for BBD. The hydrolysis rate constant for bread made with BP (~ 4 min-1) was about twofold faster than for BBDY. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-021-05206-1.