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This research aimed to characterize and apply a fiber obtained from a fruit residue as a fat substitute in ice creams. The by‐product of the processing of red pitaya pulp dried at low temperature proved to be a source of dietary fiber, with high soluble fiber content, and to have suitable technological properties, which is indicative of its potential as a fat replacer in foods, besides containing antioxidant properties. The addition of the fiber into strawberry ice cream improved overrun and rheological behavior of the sample with 73.5% fat reduction and resulted in a product with high overall acceptability, demonstrating that it is an alternative for the food industry to reduce fat with an increase in the nutritional value of products. Practical applications This work aimed to highlight the potential application of the flour produced from the red pitaya processing residue as a fat substitute in strawberry ice cream. The peel powder presented appropriate technological characteristics, besides a high fiber content, indicative that it can be used in several products in order to improve its nutritional value and physical parameters. The ice creams developed had a proper sensory evaluation, suggesting that they could be produced by the food industry and placed on the market for sale to specific consumers worried about healthy and adapted at a calorie‐reduced diet.

Optimization of thermal processes relies on adequate degradation kinetic models to warrant food safety and quality. The knowledge on thermal inactivation kinetics of antimicrobial peptides is necessary to allow for their adequate use as natural biopreservatives in the food industry. In this work, thermal inactivation of the previously characterized bacteriocin-like inhibitory substance (BLIS) P34 was kinetically investigated within the temperature range of 90-120 degrees C. Listeria monocytogenes ATCC 7644 was used as the indicator microorganism for antimicrobial activity. Applicability of various inactivation models available in the literature was critically evaluated. The first-order model provided the best description of the kinetics of inactivation over the selected temperatures, with k values between 0.059 and 0.010 min(-1). D and k values decreased and increased, respectively, with increasing temperature, indicating a faster inactivation at higher temperatures. Results suggest that BLIS P34 is thermostable, with a z value of 37.74 degrees C and E(a) of 72 kJ mol(-1).

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a b s t r a c tBacillus sp. P34, a strain isolated from aquatic environments of Brazilian Amazon basin, produces a bacteriocin-like substance (BLS) which was encapsulated in nanovesicles prepared from partially purified soy lecithin. The efficiency of free and encapsulated BLS P34 to control the development of L. monocytogenes and maintenance of antimicrobial activity was assessed over time in milk. The antimicrobial activity of free and encapsulated BLS P34 decreased approximately 50% after 4 days of storage (<4 C) in skim and whole milk. After this period there was not significant loss of activity up to 21 days. The viable counts of Listeria monocytogenes in skim and whole milk containing 3200 AU/ml of free or encapsulated BLS P34 were always lower than those observed in controls without bacteriocin at both 30 C and 7 C. At 1600 AU/ml concentration, free and encapsulated BLS P34 were inhibitory to L. monocytogenes in skim milk, when compared with the control at 7 days. Nanovesicle-encapsulated and free BLS P34 shows potential use as biopreservative for application in milk-derived products.