Juá (Ziziphus joazeiro Mart.) mucilage and juá by-product phenolic extract improve quality parameters and retain bioactive compounds in fresh-cut pineapple during storage.

This study evaluated the effects of coatings with juá mucilage (JM), juá mucilage incorporated with phenolic extract from juá (JMPE), and juá mucilage with gum arabic (JM-GA) on quality parameters, bioactive compounds and antioxidant activity of fresh-cut pineapple during 9 days at 5 ± 1 °C. JM and JMPE coatings were effective in reducing enzymatic activity, consequently reducing changes in fruit color compared to uncoated fresh-cut pineapple (C). JM coating was more efficient in reducing metabolic activity with the lowest conversion of sugars into glucose, fructose and organic acids. In addition, JMPE coating showed the highest retention of phenolics. On the other hand, JM had a minor reduction in antioxidant activity in FRAP (39.55 %) and ORAC (33.46 %) assay compared to other coatings (p ≤ 0.05). Findings indicate that JM and JMPE are promising for application to preserve the overall quality and to extend the shelf life of fresh-cut pineapple.

Juá fruit (Ziziphus joazeiro) from Caatinga: A source of dietary fiber and bioaccessible flavanols.

Fruits from Ziziphus joazeiro from Mata Paraibana (MP), Borborema (BB), Agreste (AG) and Sertão Paraibano (SP) were assessed to determine their morphological characteristics, nutritional composition, content and bioaccessibility of phenolic compounds and antioxidant activity. In general, juá fruits presented ovoid shape, high moisture (65.33-72.53%), low acidity, with succinic acid being the predominant organic acid, and high dietary fiber content (8.98-10.81%), mostly insoluble fibers (5.72-8.02%). Fruits from MP presented the highest amounts of free phenolic compounds (24.27 mg/100 g) and the highest antioxidant activity in the DPPH, FRAP and ORAC assays. In MP fruits, epigallocatechin gallate (12.04 mg/100 g) was the major compound, while in fruits from other states, phenolic compounds were the major compounds. The bioaccessibility of catechin, epicatechin, epicatechin gallate, epigallocatechin gallate, procyanidin and syringic acid varied among fruits from different regions. Fruits from SP presented the highest phenolic content in the bioaccessible fraction and highest antioxidant activity in all assays. The findings of this study indicate that juá is a non-acidic fruit with highest moisture, source of fiber, majority insoluble fibers and bioaccessible flavanols.

Effects of probiotics on the content and bioaccessibility of phenolic compounds in red pitaya pulp.

This study assessed the effects of the incorporation of Lactobacillus acidophilus LA-05 or Bifidobacterium animalis ssp. lactis BB-12 in the content and bioaccessibility of phenolics in red pitaya pulp. The oxygen radical absorbance capacity (ORAC) of the dialyzed (bioaccessible) fraction of red pitaya pulp fermented by these probiotics was also assessed. After 48 h of cultivation in red pitaya pulp, the pH and sugar contents decreased, while organic acids and viable counts of the tested probiotics increased (p < 0.05). After exposure to simulated gastrointestinal conditions the viable counts of L. acidophilus LA-05 and B. lactis BB-12 in fermented red pitaya pulp were close to 8 and 7 log CFU/mL, respectively. Fermentation with probiotics decreased (p < 0.05) the contents of phenolic acids and flavonoids in red pitaya pulp. Both, L. acidophilus LA-05 and B. lactis BB-12 increased the presence of phenolics in the non dialyzed fraction of the red pitaya pulp. The bioaccessibility of catechin, epigallocatechin gallate, and procyanidin B2 increased (p < 0.05) in red pitaya pulp fermented by L. acidophilus LA-05 or B. lactis BB-12. The bioaccessible fraction of red pitaya pulp fermented by L. acidophilus LA-05 or B. lactis BB-12 showed higher antioxidant activity than that of the non-fermented red pitaya pulp. These findings indicate the fermentation of red pitaya by probiotics as an alternative to increase the bioaccessibility of specific phenolics, as well as the antioxidant activity in this fruit.