Antimicrobial and antioxidant properties of pullulan film containing sweet basil extract and an evaluation of coating effectiveness in the prolongation of the shelf life of apples stored in refrigeration conditions

• Pullulan film gained antimicrobial and antioxidant properties after incorporating sweet basil extract (SBE).
• We observed great antifungal efficacy of pullulan coating containing SBE on apples.
• The application of coatings to apples also reduced changes of quality parameters.
• Coated apples presented better overall preference than uncoated apples.

The antimicrobial and antioxidant activities of pullulan films containing sweet basil extract (SBE) at varying concentrations were examined in the paper. Additionally, the content of bioactives in SBE was determined. A strong correlation was noted between SBE concentrations in the film and the obtained film thickness. Pullulan film containing SBE was characterized by a smooth surface as well as a uniform and compact internal structure. The study involved an examination of the effectiveness of pullulan coatings containing 24 mg SBE/cm2 on the prolongation of the shelf life of “Jonagored” apples. Pullulan coating with SBE was found to offer low antibacterial activity against mesophilic bacteria and good antifungal protection against Rhizopus arrhizus on apple surfaces. This coating also contributed to a reduction in weight losses and lower changes in the color and soluble solids of fruits during storage. Apples with pullulan enriched SBE coating presented better overall preference parameters.Industrial relevanceThe consumers express an increasing aversion and objections towards an application of chemical means in order to prolong the durability of food products. This prompts food producers to search for new methods of preventing raw materials against harmful microbial activity. Plant extracts, due to their chemical variability, ensure unlimited possibilities of microorganism growth control. An application of natural plant extracts combined with edible coatings for fruit and vegetable durability prolongation may find an acceptance among the consumers. Incorporation of plant extract to edible coating ensures slow release of bioactives on food surface, i.e. at the site of the highest microbiological food changes. Pullulan is a natural polysaccharide, a carrier of small energy amounts, forming glossy, colorless and flavorless films, resistant to oils and impermeable for oxygen. The authors decided to elaborate the procedure concerning an application of edible pullulan coating combined with sweet basil extract for an elongation of apple durability, which will improve the quality of fresh fruits during their storage and in the trade.