Stabilization and valorization of tomato byproduct: A case study for the bakery industry

Worldwide, tomato production is estimated at 180 million tons per year, which generates a byproduct with highly variable characteristics and volumes. According to the principles of the circular economy, a semi-industrial method for the integral use of the tomato byproduct as an ingredient in the bakery industry is proposed. Using two different dehydration processes (convection or freeze-drying), a tomato byproduct formed by peels and seeds was stabilized and ground into flours that were used as ingredients in focaccia-type flatbread elaboration through a wheat flour partial substitution trial (from 0% to 20% w/w). Based on the kinetics of convection drying and remaining lycopene content results, conditioning of the byproduct at 60°C was proposed. The higher the percentage of substitution, the greater the firmness of the flatbread. However, the cutting force was maximum with 15% replacement. The flatbreads with 5%-15% replacement were rated positively according to consumer acceptance studies. Substitution of up to 15% tomato byproduct is suggested for the formulation, as the higher the byproduct flour content, the lower the volume, the higher the firmness, and reddish-brown tones. Realistically, for the industrial setting, this processing proposal reached the whole food chain, from field to fork. PRACTICAL APPLICATION: Based on the circular economy and considering the whole food chain, a case study is proposed to prove the usefulness of tomato byproduct flour implementation in bakery with consumers' acceptance. Once the tomato byproduct was dehydrated by convection drying and ground, the flour was used to make focaccia-type flatbread. Up to 15% of tomato byproduct flour addition was accepted by consumers. Considering the tons of tomato byproducts generated worldwide and the overall bakery possibilities, this case shows industrial steps toward sustainable food production practices.

The Sensory Profiles of Flatbreads Made from Sorghum, Cassava, and Cowpea Flour Used as Wheat Flour Alternatives

Sorghum, cowpea, and cassava are underutilised gluten-free sources of flour that have the potential to be used in bread products in sub-Saharan Africa. Excessive wheat imports affect the economies of countries in sub-Saharan Africa, driving the search for wheat flour alternatives. To extend the use of sorghum, cowpea, and cassava flours toward bread production, it is vital that the sensory properties of these flours are better understood. A trained sensory panel evaluated and described the sensory properties of flatbread models prepared from red non-tannin sorghum, fractions (whole and dehulled) of two cowpea varieties, cassava starch, and designated flour composites. The composites were prepared using cassava starch and sorghum flour at 0%, 35%, and 70%, respectively, with 30% cowpea flour. The addition of sorghum intensified sorghum aroma in flatbread, while cowpea flours contributed a beany flavour. Flatbreads from cassava-cowpea composites had a chewier and rubberier mouthfeel, an intense fermented aroma and flavour, and a sour aftertaste compared to single flours, but were most similar to the wheat flatbread, with a residual beany flavour. Information from this study can guide food product developers toward developing new bread products from sorghum, cassava, and cowpea composite flours, thereby moving Africa towards a more sustainable food system. Further research on the effects of the sensory characteristics on consumer liking of the flatbreads is needed.

The Use of Iron-Enriched Yeast for the Production of Flatbread

The most common cause of iron deficiency is an improperly balanced diet, in which the body’s need for iron cannot be met by absorption of this element from food. Targeted iron supplementation and food fortification may be the main treatments for iron deficiency in the population. However, many iron-rich supplements and foods have low bioavailability of this element. In our study, we used yeast enriched with iron ions to produce flatbread. The yeast cells accumulated iron ions from the medium supplemented with Fe(NO₃)₃·9H₂O, additionally one of the cultures was treated with pulsed electric field in order to increase the accumulation. The potential bioavailability of iron from flatbread containing 385.8 ± 4.12 mg of iron in 100 g dry mass was 10.83 ± 0.94%. All the flatbreads had a moderate glycemic index. There were no significant differences in antioxidant activity against DPPH^• between flatbread with iron-enriched and non-iron-enriched yeast. Sensory evaluation showed that this product is acceptable to consumers since no metallic aftertaste was detected. Iron enriched flatbread can potentially be an alternative to dietary supplements in iron deficiency states.

Rheological, textural, and technological modifications in wheat unleavened flatbread substituted with extruded finger millet

Finger millet incorporation in wheat flour increases the nutritional value of flatbread and provides health benefits. However, it also has a detrimental effect on the quality of flatbread. The present study evaluates the effect of extruded finger millet (EFM) over unextruded finger millet (UFM) flour on pasting, textural and rheological properties of composite dough and their impact on the quality of flatbread. EFM modified the dough handling properties leading to higher viscoelastic moduli and elastic share of compliance. In addition, a significant reduction in firmness and increment in extensibility of dough was also observed. The flatbread prepared by substituting 20% of EFM in wheat flour exhibited better puffing and lower resistance, shrinkage, and baking time in comparison to flatbread prepared with UFM at the same level of substitution. The sensory score for the same was at par with the control whole wheat flatbread. Results suggest that the substitution of EFM flour in composite dough maintains the rheological and technological quality of composite wheat flatbread.

Influence of Waxy (High Amylopectin) and High Protein Digestibility Traits in Sorghum on Injera Sourdough-Type Flatbread Sensory Characteristics

Injera, an East African leavened sourdough fermented pancake has remarkable textural properties despite being made from non-wheat flours. However, teff flour, which produces the best quality injera, is expensive and limited in availability. The effects of waxy (high amylopectin) and high protein digestibility (HD) traits in sorghum on injera quality were studied. Eight white tan-plant sorghum lines expressing these traits in various combinations and three normal sorghum types were studied, with teff flour as reference. Descriptive sensory profiling of fresh and stored injera revealed that injera from waxy sorghums were softer, spongier, more flexible and rollable compared to injera from normal sorghum and much closer in these important textural attributes to teff injera. Instrumental texture analysis of injera similarly showed that waxy sorghum injera had lower stress and higher strain than injera from normal sorghum. The improved injera textural quality was probably due to the slower retrogradation and better water-holding of amylopectin starch. The HD trait, however, did not clearly affect injera quality, probably because the lines had only moderately higher protein digestibility. In conclusion, waxy sorghum flour has considerable potential for the production of gluten-free sourdough fermented flatbread-type products with good textural functionality.