Estudo da secagem de polpa de juá (Ziziphus joazeiro) em leito de jorro e sua aplicação em barras de cereais.

Abstract

The juazeiro fruits are edible, being widely consumed in natura by the sertanejo of Northeast Brazil, however, it is a seasonal, climacteric, highly perishable fruit. There are few studies and researches in the literature on juá, mainly on the bioactive components and its antioxidant activity, as well, there are few that verify the effects of drying on the content of functional compounds of this fruit and none on the drying in spouted bed . Given this context, the present research aimed to obtain the pulp powder from the juá by drying it in a spouted bed and its use in the production of a food with an innovative functional appeal, the cereal bar. The drying took place in a cone-cylindrical column bed dryer. The spout column was loaded with low density polyethylene used as inert. The parameters considered to trace the fluid dynamic behavior of the equipment during the drying process were the pressure drop of the system; the height of the ring; the height of the fountain; the speed and humidity of the outlet air. The experiments were carried out at a fixed air speed of 1.6 times the minimum spurt speed, with temperatures of 50 ºC, 70 ºC and 90 ° C for 230 minutes. The process yield calculation was carried out, as well as the determination of the fruit's physical and physical-chemical properties of the pulp, with emphasis on total phenolic compounds, antioxidant activity of both the fruit and the powdered pulp. The juá pulp drying process showed a good yield for all temperatures evaluated, with values between 67.17 and 78.22%. The temperatures of 50 ° C and 70 ° C showed the best results and show no statistical difference between them, however the sample obtained at the temperature and 50 ° C showed better results also for the content of bioactive compounds, which was chosen for the preparation of cereal bars. For the preparation of cereal bars, four formulations were used, where the sample called F0 did not contain the addition of powdered juá pulp. coarse, hydrolyzed collagen and powdered soy extract were partially replaced by powdered juá pulp, in the proportions of 10, 20 and 30% respectively. A short online questionnaire was carried out with 115 volunteers on the profile of cereal bar consumption and the participants' knowledge of juá and its benefits, in addition to assessing the consumer's perception of acceptability and intention to purchase enriched cereal bars. with juá pulp powder. The bar was also evaluated for texture, colorimetric, proximate composition and total energy value parameters. The nutritional value of cereal bars enriched with juá pulp powder indicates their use as energy bars, due to the significant content of lipids, proteins and carbohydrates in their formulations. Thus, the bars prepared in the present study can be an alternative for a nutritious food product, in addition to adding value to a native fruit, with high nutritional value and functional appeal, although little explored.