Apple pomace (AP), a by-product of apple processing, constitutes 20-35% of the fruit's fresh weight. Its disposal poses considerable environmental and logistical challenges for the industry. However, AP is a rich source of compounds with biotechnological potential, particularly pectin, a major dietary fiber known for its gel-forming and prebiotic properties.

This study aimed to evaluate the impact of adding pectin to Not-From-Concentrate (NFC) apple juice on the viability of two probiotic bacteria: Lactiplantibacillus plantarum ATCC 8014 (LP) and Lacticaseibacillus casei ATCC 393 (LC). Comparisons between apple pomace-derived and commercial pectin were performed.

Pectin was extracted from AP powders using a 1:30 acidified water (pH 2)-to-AP ratio, using citric acid. The extraction process involved a sonication step (40°C, 25 min) followed by heat treatment (90°C, 70 min). The extracted pectin was characterized according to the following: equivalent weight (Peq), methoxyl content (MeO%), degree of esterification (DE%), and galacturonic acid content (AUG%), besides the yield of the process. Pectin was then added to commercial NFC apple juices at 1% w/v. Probiotic strains (107 CFU/mL) were incorporated into the pectin-enriched juices, and their viability was monitored weekly over four weeks under refrigeration.

The pectin extraction yield was 11%, and its characterization showed values of Peq 115 g/eq, MeO% 12%, DE% 46%, and AUG% 153%. Probiotic survival with pectin enrichment was higher compared to the controls without pectin. Notably, AP pectin yielded equal or higher survival rates than commercial pectin: 87% for LC and 100% for LP, compared to 82% and 100%, respectively, for commercial pectin. These findings are highly promising, particularly given the vast volumes of by-products generated by the apple industry. This approach offers a straightforward implementation strategy, simultaneously mitigating waste and enhancing the dietary fiber content of functional juices.