Table 1.

Study and main findings of vegetable and fruits by-products utilization as functional ingredients in development of bread.

Product developed	Vegetable and fruit by-products	Study and main findings	References
Whole wheat bread	Black bean seed coat (BBSC)	In the study, 0.5% of black bean seed coat (BBSC) was incorporated for the development of whole wheat bread. The study found no significant difference in terms of baking properties and texture parameters after the incorporation of BBSC. However, the crumb color showed significantly lower value in L*, a*, and b*score. Besides, all attributes during the sensory evaluation did not have significant difference with control except color, where the new product obtained higher score than control. The study also showed that more than 80% of flavonoids, saponins and anthocyanins were retained in baked bread, incorporated with BBSC.	(38)
Wheat bread	Flaxseed hulls (FH)	In the study, 1–5% flaxseed hulls (FH) were incorporated into wheat bread. The phenolics content was increased by 93% and the radicals scavenging ability as well as reducing power, increased by 176 and 220%, respectively with the incorporation of 5% of FH. Besides, the proteins digestibility decreased to 8%. Based on the in vitro starch digestibility, expected glycemic index was not significantly affected with enrichment of FH. It was found that FH enrichment decreased loaf volume and increased crumb hardness which affected texture of bread. In the sensory evaluation, no significant difference was observed on the overall acceptability of bread with the incorporation of FH up to 3%.	(12)
Bread	Pea hulls (PH)	Up to 10% of small-grained pea hulls (PHS) and coarse-grained hulls (PHC) were incorporated in bread. The study showed that pea hulls (PH) contained high total dietary fiber (TDF), that is, 70.69% in PHS and 93.29% in PHC, respectively. The total baking lost and crumb porosity decreased with increasing amount of both PHS and PHC. The authors found that the functional properties of crust and crumb were affected with the addition of PH. In addition, TDF of bread increased to 17.7 and 21% with the addition of 10% PHS and 10% PHC respectively. In the sensory evaluation, the acceptability of bread decreased with increasing amount of both PHS and PHC. The study found that up to 10% PH could be incorporated in bread, with acceptable physical properties and sensory values, without altering the color.	(73)
Wheat bread	Potato peels (PP)	The authors used 0, 4, 8, and 12% of potato peels (PP) to be incorporated in wheat bread. An increase of PP in the formulation decreased the baking loss and bread volume. The incorporation of 12% PP significantly increased the dietary fiber (5.3–10.8 g/100 g DM) and cellulose (0.5–2.5 g/100 g DM). The study found that the texture profile of bread was affected with the incorporation of PP, where the hardiness, gumminess, modulus and adhesiveness were increased and the deformation energy, and springiness was reduced. Based on the sensory evaluation, 8% PP substitution had a better acceptability.	(44)
Wheat bread	Pomegranate peel (PGP)	Up to 10% of pomegranate peel (PGP) was incorporated in wheat bread. The antioxidant levels of bread increased from 1.8 mmol TEAC per g (0% PGP) to 6.8 mmol TEAC per g (10% PGP) and remained constant under 5 days storage. Besides, the concentration of free radicals decreased with increasing PGP substitution. In the sensory evaluation, no significant difference was observed as compared to the control in terms of acceptability for all attributes at all substitution level except taste and mouthfell of 10% substitution as it caused a significantly lower score. The authors indicated that 2.5% of PGP substitution showed the highest acceptability with acceptable antioxidant value.	(74)
Bread	Tomato pomace (TP)	In this study, 6 and 10 % of tomato pomace (TP) were incorporated in bread. Based on the preliminary analysis, TP contained 174.12 mg/kg lycopene, 32.66 mg/kg β-carotene, 111.89 mg/kg ascorbic acid and 865.77 mg GAE/kg total phenolics. Besides, TP was found to be rich in minerals including potassium, magnesium, calcium and sodium. The moisture content, titratable acidity and bread crumb elasticity were significantly increased with the supplementation of TP, while specific volume and bread crumb porosity were found to be decreased. In term of sensory evaluation, the acceptability of bread was slightly decreased with the increasing supplementation of TP. It was found that bread with 6% TP supplementation showed high sensory results and acceptable physiochemical properties.	(75)
Bread	Grape pomace (GP)	In the study, 2, 5, and 10 of grape pomace (GP) were incorporated in bread. The incorporation of GP significantly increased the antioxidant activity of bread samples, from 11.06% (0% GP) to 55.64% (10% GP). Besides, the total phenolic content of bread increased by more than 150% with the 10% of GP fortification. The study also found that fortification of GP significantly affected the color of crust and crumb and texture of bread. The hardness was increased while the springiness and cohesiveness were decreased with the increasing amount of GP being fortified. In term of sensory evaluation, no significant difference was observed in shape symmetry, crumb color, pore structure and odor for all samples. It was found that 2 and 5% GP-fortified bread had high acceptability, compared to the 10% of GP-incorporated bread.	(54)

L*, L* standard (indicates lightness); a*, a* standard (indicates red/green coordinate); b*, b* standard (indicates yellow/blue coordinate).