UMBU FRUIT BARS STRUCTURED WITH DIFFERENT HYDROCOLLOIDS: XANTHAN, AGAR, CARRAGEENAN AND LOW METHOXYL PECTIN

Fruits provide several nutrients for health, including vitamins, minerals, fiber and phytochemicals. Umbu is a fruit rich in vitamin C and mineral salts, with low caloric density. The fruit structure can be obtained through whole puree or fruit pulp, with the addition of hydrocolloids and sugars, reducing moisture and helping in the pulp structuring process. With this, there is a desirable change in the final product's texture with the gelling process. This work's objective consisted of elaborating and evaluating umbu structure, testing the performance of different hydrocolloids, and assessing the instrumental color and texture. For the formulation of the fruit bars, 100g of commercial umbu pulp and different hydrocolloids were used: xanthan (0.5%), agar (0.5 and 2.0%), carrageenan (0.5 and 2.0%) and low methoxyl pectin (2.0%) added of CaCl2 (0.111%). The mixture was homogenized and concentrated in an open aluminum pan coated with Teflon on a domestic stove for 7min. Then, the mixture was added in a rectangular shape measuring 170x80x13mm (length, width, thickness) and cooled. Finally, 28-mm-wide bars were cut and stored in high-density polyethylene packaging for 24h at room temperature. The instrumental color was determined in a spectrophotometer evaluating the CIE-L*a*b* system. Texture profile analysis was performed in a texturometer with SMS P/0.5R probe, probe diameter 10mm, HDP/90 platform in compression mode, speed test of 1.0mm.s-1, probe height of 20mm, distance of 18mm and force threshold of 0.02N. The results were evaluated through analysis of variance (P<0.05), and when statistically significant differences were observed, the test of Tukey was used to compare means. Based on the data, it was possible to infer that the formulations with a concentration of 0.5% of carrageenan, agar or xanthan had a less firm consistency, making it impossible to cut them into bars. Formulations containing concentrations of (2.0%) carrageenan, agar or low methoxyl pectin have a firmer consistency and appearance, suitable for cutting. Concerning luminosity, the samples varied between 51.13 and 55.56 for the L* parameter, which corresponds respectively to low methoxyl pectin (2.0%) and agar (0.5%), and there was a significant difference between the carrageenan samples (2.0%) and agar (0.5%). Regarding the a* parameter, there was a range from 7.62 to 8.72, noting that the tests with agar and carrageenan (0.5%) showed no difference. The b* parameter showed values from 29.10 to 38.82, with only low methoxyl pectin (2.0%) and agar (0.5%) showing statistical differences between the other hydrocolloids. Through the data of the instrumental texture, when using 2% of agar, the highest values of hardness (13.24N) were obtained, while for agar and carrageenan, the highest values of adhesiveness (-2.65N) and impulse (17.39N.s), respectively, which provides satisfactory performance and better potential for application in the structuring of structured fruit bars. It was possible to conclude that hydrocolloids with 2% concentrations of carrageenan, low methoxyl pectin or agar had greater stability during processing, allowing adequate gelation and improving the texture.