Application of different drying techniques to fresh-cut salad waste to obtain food ingredients rich in antioxidants and with high solvent loading capacity

Effect of Green Tea Powder on Physicochemical Properties and Glycemic Potential of Sponge Cake

Green tea powder (GTP) is rich in polyphenolic compounds, most particularly catechins. The effects of partial replacement of flour with GTP (10, 20, and 30%) on physicochemical properties, glycemic potential, and sensory attributes were investigated. Results showed a significant reduction in the moisture content, volume, and porosity of sample cakes with the increase in the GTP levels ( $P\le 0.05$ ). The utilization of GTP led to a harder texture and also darker color of sponge cake. The study showed that sponge cakes with good sensory attributes can be produced by the replacement of flour with 10% of GTP. Moreover, the glycemic potential and free radical scavenging activity of sample cakes improved as the GTP replacement increased ( $P\le 0.05$ ). GTP at 10% replacement level is recommended as it is very effective in improving the antioxidant properties, sensory attributes, and also glycemic potential.

Valorization of olive processing by-products via drying technologies: a case study on the recovery of bioactive phenolic compounds from olive leaves, pomace, and wastewater

Olive by-products are rich sources of phenolic compounds and their valorization is a favorable approach in line with sustainable development goals of the United Nations (UN) organization to promote well-being and production of healthier products; also, to deal with the environmental and economic subjects resulting in more profitability in the olive oil industry. The production of value-added ingredients from these by-products is not extensively exploited on the industrial scale. Drying is a critical pretreatment before extraction that can have a direct impact on the recovery and yield of the available bioactive compounds in olive by-products. In order to produce more stable and high quality phenolic products, encapsulation using spray and freeze drying is used. In this study, the effect of the drying process before and after extraction of bioactive compounds from olive by-products as a valuable source of phenolic compounds is reviewed. In addition, fortification using these ingredients and their incorporation in food formulations is also investigated.

Effects of Processing and Storage Conditions on Functional Properties of Powdered Blueberry Pomace

Promoting a circular economy through valorisation of food processing waste into functional ingredients is a challenge today. The combination of hot air drying with milling is a cheap and highly available option for obtaining powdered products from blueberry pomace, a residue with a large amount of fibre and a high proportion of polyphenols from the fruit. The objective of this work was to analyse the effect of drying temperature (60 °C and 70 °C) and granulometry (coarse and fine) on physicochemical properties, including antioxidant properties and monomeric anthocyanins content. The potential prebiotic effect of blueberry pomace powders, as well as their water and oil interaction properties, were also assessed. Stability of physicochemical properties over 20 weeks of storage was also evaluated. Powders obtained showed a total fibre content higher than 30% with a good proportion between insoluble and soluble fractions and a high retention of monomeric anthocyanins from fresh pomace (75% at 60 °C and 66% at 70 °C). The powders showed good water interaction properties and interesting technological properties, such as solubility and hygroscopicity, which were not affected by differences in particle size. Stability of powders’ physicochemical properties was evidenced throughout the storage period.

Valorization of Vegetable Fresh-Processing Residues as Functional Powdered Ingredients. A Review on the Potential Impact of Pretreatments and Drying Methods on Bioactive Compounds and Their Bioaccessibility

Food waste is a worldwide concern as it represents a constant threat to the environment and a serious operational problem for the food industry. The by-products of fruits and vegetables being a valuable source of bioactive compounds have the potential to be reused and reintroduced in the agri-food chain. This circular approach contributes to a sustainable production system. In this context, a collaborative project with the primary sector for the integral valorization of the waste generated in the fresh-processing vegetable lines of an agricultural cooperative is currently being developed, particularly focused on cabbage, carrot, celery, and leek. The objective of this project is to transform vegetable wastes into functional powdered ingredients and be able to use them in food formulations in order to improve the nutritional profile of foods, contributing to the development of sustainable healthy diets. Through an exhaustive bibliographic review, this research studies the influence of pretreatments, drying and in vitro digestion on the bioactive compounds of vegetable residues, with the aim of identifying the appropriate production parameters to achieve an adequate functional and physicochemical profile of the final powders.

Study on the possibility of developing food-grade hydrophobic bio-aerogels by using an oleogel template approach

The feasibility of producing food-grade hydrophobic bio-aerogels by supercritical-carbon dioxide (SC-CO₂) extraction of oil from oleogels was investigated for the first time. Medium chain triglycerides (MCT) oil was gelled using ethylcellulose (EC) at increasing concentration (10, 15, 20% w/w) and grade (EC20, 45, 100), eventually in combination with fillers. Different SC-CO₂ oil extraction procedures were tested. The acquired results show that both oleogel formulation and extraction conditions can steer the EC scaffold structure. The increase in EC concentration and grade resulted in oleogels more structurally stable to SC-CO₂ extraction. The application of a pulsed extraction procedure allowed obtaining a low-density (0.39 ​g/cm³) EC scaffold presenting 60% oil. Addition of freeze dried lettuce powder improved macrostructure homogeneity. The obtained results lay the foundations for developing food-grade hydrophobic bio-aerogels, which are expected to present unique oil absorption and bioactive delivery features.