Selected Quality Characteristics of Fresh-Cut Sweet Potatoes Coated with Chitosan during 17-Day Refrigerated Storage

Shifts in the Bacterial Community Related to Quality Properties of Vacuum-Packaged Peeled Potatoes during Storage

To reveal the potential relationship between the bacterial community and quality attributes of vacuum-packaged peeled potatoes, the bacterial community dynamics, visual quality, organic acids, flavor and volatile organic compounds (VOCs) during 12 days of storage under 10 °C were studied, and a correlation analysis was performed between the bacterial community and VOCs. During the whole storage, the dominant bacteria changed from Ralstonia, Pseudomonas, Pantoea and Comamonas to Clostridia, Clostridium, Lacrimispora, Lactococcus and Leuconostoc. The visual quality and hardness deteriorated significantly on day 12; meanwhile, lactic and acetic acid content accumulated to 0.79 and 4.87 mg/g FW, respectively. Potatoes’ flavor deteriorated severely after 8 days, as evidenced by results of an electronic nose (e-nose). A total of 37 VOCs were detected, and the total content showed an increasing trend from 2164.85 to 10658.68 μg/kg during the whole storage. A correlation analysis showed that Enterobacteriaceae, Erwinia, Lacrimispora, Lactococcus, Serratia, Pantoea, Clostridium, Flavobacterium and Clostridia were positively correlated with the biosynthesis of VOCs. In addition, 10 spoilage markers were screened according to a variable importance in projection (VIP) ≥ 1. Ethanol, which was the most abundant spoilage marker, was significantly related to Enterobacteriaceae, Erwinia, Lacrimispora and Lactococcus. The results of this study have great practical significance for prolonging the shelf life of fresh-cut agricultural produce.

The influence of edible coatings and natural antioxidants on fresh-cut potato quality, stability and oil uptake after deep fat frying

The effect of four edible hydrocolloid coatings (carboxymethyl cellulose, chitosan, pectin and gum arabic) on fresh-cut potato's colour, pH and moisture content during storage was studied. Possibility of coating enrichment with natural olive leaf extract and sodium ascorbate was also evaluated. Coatings scored as the best ones straight after coating or during storage for 7 days at 10 ± 1 °C, were used for deep fat frying of potato. Chitosan was shown to cause significant decrease in pH and browning of potato strips. Pectin was classified as good coating alone but in combination with olive leaf extract showed lower quality parameters of fresh-cut samples compared to control. Only carboxymethyl cellulose and gum arabic itself or enriched with olive leaf extract or sodium ascorbate were shown not to affect colour, pH and moisture during storage. Moreover, these coatings significantly reduced fat content in deep fat fried potato strips, without influence on L*, b*, whiteness index (WI), and ΔE.

Ultrasound treatment inhibits browning and improves antioxidant capacity of fresh-cut sweet potato during cold storage

Ultrasound treatment could inhibit browning of fresh-cut sweet potato by reducing PPO and POD activities while improving total antioxidant capacity.

Review of antimicrobial and antioxidative activities of chitosans in food

Interest in chitosan, a biodegradable, nontoxic, non-antigenic, and biocompatible biopolymer isolated from shellfish, arises from the fact that chitosans are reported to exhibit numerous health-related beneficial effects, including strong antimicrobial and antioxidative activities in foods. The extraordinary interest in the chemistry and application in agriculture, horticulture, environmental science, industry, microbiology, and medicine is attested by about 17,000 citations on this subject in the Scopus database. A special need exists to develop a better understanding of the role of chitosans in ameliorating foodborne illness. To contribute to this effort, this overview surveys and interprets our present knowledge of the chemistry and antimicrobial activities of chitosan in solution, as powders, and in edible films and coating against foodborne pathogens, spoilage bacteria, and pathogenic viruses and fungi in several food categories. These include produce, fruit juices, eggs and dairy, cereal, meat, and seafood products. Also covered are antimicrobial activities of chemically modified and nanochitosans, therapeutic properties, and possible mechanisms of the antimicrobial, antioxidative, and metal chelating effects. Further research is suggested in each of these categories. The widely scattered data on the multifaceted aspects of chitosan microbiology, summarized in the text and in 10 tables and 8 representative figures, suggest that low-molecular-weight chitosans at a pH below 6.0 presents optimal conditions for achieving desirable antimicrobial and antioxidative-preservative effects in liquid and solid foods. We are very hopeful that the described findings will be a valuable record and resource for further progress to improve microbial food safety and food quality.