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The effects of different hydrothermal pretreatments on the physical chemical characteristics and drying kinetics of red rice starch (Oryza sativa L.) were investigated.The hydrothermal pretreatments chosen include the cooking, autoclave, and steam explosion processes. To obtain the starch in powder form, the pastes were dried at a temperature of 50°C with an air speed of 1.0 m/s. The mathematical models (empirical and diffusive) were adjusted to the experimental data. The starches were submitted to extraction yield, color, water binding capacity, and proanthocyanidins. The values for the diffusivity are between 3.08 × 10 −7 and 2.74 × 10 −6 m 2 /min for treatments. The pretreatments of cooking in the grain and autoclave in the starch gave better results than the other studied treatments (formulations), presenting shorter drying time (450 and 510 min) and higher yield (48.60% and 53.54%), respectively. With the application of pretreatments, it is possible to save energy and reduce thermal damage. Novelty impact statement:The results obtained in this study reveals the application autoclave pre-treatment in red rice starch effectively saves energy and reduces thermal damage as the drying time is shortened. In addition, the drying process information can be used when designing future new equipments. Highlights• The effects of different hydrothermal pre-treatments on the physical chemical characteristics and drying kinetics of red rice starch (Oryza sativa L.) were investigated.• The hydrothermal pre-treatments included the cooking, autoclave and steam explosion processes.• The pre-treatments of cooking (grain) and autoclave (starch) gave the best results, presenting shorter drying time (510 and 450 min) and higher yield (53.54% and 48.60%), respectively. | INTRODUC TI ONRice is a staple food consumed in many countries around the world due to its nutritional composition (Pereira-Caro et al., 2013). Presenting a series of pigmented varieties, among which red rice has attractive characteristics such as high content of proteins, minerals, vitamins, starch, and bioactive compounds (anthocyanins, proanthocyanidins, and carotenoids) (Sumczynski et al., 2016;Butardo et al., 2019).One of the carbohydrates most found in rice is starch, a polysaccharide that exhibits interesting properties because of its biodegradability, biocompatibility, and nontoxicity (Afolabi et al., 2012).

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Probiotic foods offer many benefits to human health, causing increased interest in the development of new food products that exploit such benefits. However, traditional dairy foods are being replaced by other non-dairy foods to provide additional sources of benefits provided by bioactive molecules. Therefore, the objective of the present work was to study the production process of a probiotic fruit drink and then microencapsulate the probiotic pulp to stabilize the drink further. Passion fruit pulp (Passiflora edulis Sims f. flavicarpa Deg.) was fermented with Lactobacillus reuteri under different temperature conditions in combination with different pHs to find the best fermentation conditions. Different from dairy sources, the optimal conditions for the growth of Lactobacillus reuteri in the passion fruit pulp were found to be 30 °C at pH 3.18, where phenolic compounds could also be used as a secondary metabolic pathway. Spray-drying was performed using different conditions for microencapsulation. Process yields and Lactobacillus reuteri survival showed the dependency of droplet sizes, whereas phenolic compound retention was increased when higher amounts of gelatin were used. Therefore, the development of a new food product comprising a powdered fruit pulp rich in probiotic and phenolic compounds was possible.

Incorporation of probiotic bacteria in food is a challenge for the industry, given the sensitivity of probiotic cultures to process conditions. The objective of this study was to coat papaya slices with probiotic filmogenic solution to obtain dehydrated probiotic papaya slices. The probiotic filmogenic solution was applied as an edible coating on papaya slices before drying operation at temperatures of 50, 60, and 70°C. The Page model showed the best fit for all kinetics (R² > 0.9988). The use of filmogenic solution to incorporate the probiotic in papaya slices showed satisfactory results, with a reduction of 1.30 LogCFU g −1 at the end of drying at 70°C, reduced shrinkage, resulting in greater conservation of their structure and compounds phenolics. The thermodynamic properties indicate that the coated papaya slices need more energy to start the diffusion process and have a darker color and firmer texture profile. Novelty impact statement:The difference of this study is the evaluation of the potential use of a filmogenic solution based on gelatin and inulin in the incorporation of probiotic in dried fruit. In addition, the use of edible coating as a pretreatment for drying fruits gives interesting technological characteristics to the dried product, increasing its nutritional value.