Utilization of by-products and alternative raw materials for production of innovative bakery products

Abstract

Bakery products are popular snack foods, consumed worldwide, which contain refined wheat flour as their main ingredient. Due to their low nutritional value, they could be used for enrichment with health-promoting local raw materials and by-products (functional ingredients) in order to make them healthier and more sustainable. The main goal of the thesis was to investigate the effects of partial wheat substitution with alternative ingredients (barley, chickpea, lupin, cowpea, and yellow split pea flours) and agricultural by-products (grape seed and olive stone flours) on the properties and quality characteristics of bakery products. The thesis focused mainly on crackers as commonly consumed bakery goods. Specifically, the research evaluated the properties of the products throughout their production/processing stages (flours, dough and final product). In addition, the use of sustainable packaging materials, in conjunction with enrichment with functional ingredients, was investigated for testing their impact on the products’ shelf-life. Sensory effects of sustainable packaging were also evaluated, as well as material strength, to assess the feasibility of packaging materials. Furthermore, eye-tracking technology was employed for assessing consumer acceptance and focus of functional crackers. The study findings show that understanding the functional properties of alternative to wheat flours and their effects on dough and final product can help in the design and optimization of food products, targeting desired processing and quality outcomes. Enrichment with barley and chickpea flour resulted in crackers with harder texture and equivalent lightness values to control, while crackers with grape seed and the higher level (30%) of olive stone flour had softer texture and high total color difference. In cases where the texture or color of the product was affected, this was dependent on the type of flour and the level of wheat substitution. Most functional flours resulted in darker and diverse color profiles. The use of sustainable materials (such as edible chitosan films) for the packaging of crackers preserved the characteristics of the products and their stability throughout their shelf life to almost the same extent as conventional packaging. The results showed that information about packaging sustainability results in positive consumer perception and emotions. Nutritional information was also found to be important based on eye-tracking findings. The nutritional label of crackers attracted most of the attention of consumers. Although the control sample (100% wheat cracker) was visually attended the longest, consumer acceptability was similar between all products. As the nutritional content in the GDA labels of all crackers was similar, consumers may have perceived all products as of equivalent nutritional value. Visual attention appeared to be driven by personal motives. The study provides evidence that the right combination of functional flour type and ratio can be used to improve product quality and specific cracker characteristics. Sustainable packaging materials as well as appropriate nutritional and sustainability labelling can be used to further enhance product sustainability and help attract attention of consumers.