Use of calcium carbonate-nanoparticle-longkong peel extract in edible coating to delay longkong fruit browning

The effect of calcium carbonate (CaCO3)-nanoparticle-longkong peel extract (LPE) coating on quality and browning of longkong after harvesting were evaluated. Edible coating (carrageenan) was used as a component of 1 mM CaCO3 and 2.00 mg LPE. Longkongs were coated with 0 (control), 1 and 2% carrageenan and storing them at 13°C and 90-95% RH for 14 days. Longkong were analyzed for changes in browning pigment, L* value, pH, total phenolic content, polyphenol oxidase (PPO) and total sugar. The results showed longkong coating with 1 and 2% carrageenan (CGN) lower browning pigment, which correlated with a decrease in PPO and total phenolic content than control. However, longkong coating with 1% CGN delayed browning more than longkong coating 2% CGN during ten days of storage. While the sugar was significantly higher in control compared to 1 and 2% CGN. Longkong treated with 1 and 2% CGN showed no significantly a decrease in pH when compared to the control fruit

Enhanced survival of probiotics by encapsulation with plant extracts during foam-mat drying and under simulated gastrointestinal conditions

Survival of probiotic bacteria, Pediococcus pentosaceus ARG-MG12 encapsulated in sodium alginate beads with different plant extracts (onion, soybean, and lotus root) were tested under simulated gastrointestinal conditions compared with free cells. Encapsulated P. pentosaceus ARG-MG12 in sodium alginate solution with onion and soybean extracts revealed the highest survival under bile salt. The survival increased proportionately with increasing extracts concentrations. Microencapsulation enhanced acidic survival of all probiotic strains compared to free cells. P. pentosaceus ARG-MG12 coencapsulated with 3% soybean extracts showed the highest survival of 9.98 log CFU/mL (p < 0.05) after bile salt exposure for 3 hr, while the control including microencapsulated cells without extracts exhibited 8.66 log CFU/mL of survival. Alginate coating of the soybean extracts co-encapsulated probiotic increased survival during foam-mat drying at 70°C to 98.39% compared to that of uncoated which showed 87.55% survival. Co-encapsulated P. pentosaceus ARG-MG12 stored in hard gelatin capsule and aluminium foil bag at 8°C for eight weeks showed higher survival than room temperature

Genotypic and phenotypic diversity of Pediococcus pentosaceus strains isolated from food matrices and characterisation of the penocin operon

Lactic acid bacteria (LAB) are widely used in the food industry. Pediococcus spp. belong to the LAB group and include several species that are essential for the quality of fermented food. Pediococcus pentosaceus is the species that is most frequently isolated from fermented food and beverages but its uncontrolled growth during food fermentation processes can contribute to undesired flavours. Hence, the characterisation of these bacteria at the strain level is of great importance for the quality of fermented products. Despite their importance, misidentification at the species level is common for members of the genus Pediococcus. To clarify the taxonomic relationships among strains, a multilocus sequencing approach was developed for the characterisation of a collection of 29 field strains, 1 type strain and 1 reference strain of P. pentosaceus isolated from food. These strains were also tested for several phenotypic properties of technological interest and for the production of bacteriocins. The chromosomal operon involved in the synthesis of the bacteriocin penocin was also investigated. The present study enabled a good genomic characterisation, identifying 17 sequence types, with an overview of phenotypic characteristics related to different technological abilities, and also provides a thorough characterisation of the operon involved in penocin production