Impact of Sweet Potato Starch-Based Nanocomposite Films Activated With Thyme Essential Oil on the Shelf-Life of Baby Spinach Leaves

Abstract

Salmonella Typhimurium (S. Typhi) and Escherichia coli (E. coli) have been responsible for an increasing number of outbreaks linked to fresh produce, such as baby spinach leaves, in the last two decades. More recently, antimicrobial biodegradable packaging systems have been attracting much attention in the food packaging industry as eco-friendly alternatives to conventional plastic packaging. The objective of this study was to evaluate the effect of antibacterial nanocomposite films on inoculated spinach leaves and on the sensory properties of these leaves during eight days of refrigerated storage. In this study, an antibacterial film comprised of sweet potato starch (SPS), montmorillonite (MMT) nanoclays and thyme essential oil (TEO) as a natural antimicrobial agent was developed. Our results showed that the incorporation of TEO in the film significantly (p < 0.05) reduced the population of E. coli and S. Typhi on fresh baby spinach leaves to below detectable levels within five days, whereas the control samples without essential oil maintained approximately 4.5 Log colony forming unit (CFU)/g. The sensory scores for spinach samples wrapped in films containing TEO were higher than those of the control. This study thus suggests that TEO has the potential to be directly incorporated into a SPS film to prepare antimicrobial nanocomposite films for food packaging applications.

Efficacy of Sweet Potato Starch-Based Coating to Improve Quality and Safety of Hen Eggs during Storage

“…In fact, SPS-based coatings containing 6% TEO exhibited higher bactericidal or bacteriostatic activity compared to 2% or 4% TEO. The findings in this study are in agreement with those of Issa et al [5], who highlighted that 6% TEO exhibited potent antibacterial activity against major food-borne microbes. The present study further showed that the synergistic antibacterial activity of SPS and TEO was evident with 4% and 6% TEO.…”

“…The terpenoids are active against a broad spectrum of microorganisms. The antimicrobial action of phenolic compounds, such as thymol and carvacrol, is expected to cause structural and functional damages to the cytoplasmic membrane [5].…”

“…These compounds are effective antimicrobials and have no allergenic potential. Our previous research has shown that thyme essential oil (TEO) has strong antimicrobial activity against species of Salmonella [5]. TEO does not impose any risk of allergenicity and has no adverse effects on humans, so it is recognized as safe (GRAS) by the European Commission (EC) and the United States Food and Drug Administration (USFDA) [6].…”

INCORPORATION OF ESSENTIAL OILS FROM Piper aduncum INTO FILMS MADE FROM ARROWROOT STARCH: EFFECTS ON THEIR PHYSICOCHEMICAL PROPERTIES AND ANTIFUNGAL ACTIVITY

“…Biodegradable films were obtained by the casting method, in agreement with the methodology proposed by Issa and his collaborators, 17 with some modifications. In order to obtain films, 5 g commercial arrowroot starch was dissolved in 100 mL distilled water; the mixture was moderately agitated at room temperature (25 °C).…”

Sweet Potato Starch‐Based Nanocomposites: Development, Characterization, and Biodegradability

“…Active packaging that incorporates natural antimicrobial agents has attracted more attention as a replacement for synthetic agents in the food packaging industry. In our previous study, thyme ( Thymus vulgaris ) essential oil exhibited strong antibacterial and antioxidant activities . Therefore, the incorporation of nanoclays and natural antimicrobials into biopolymer films makes them comparable to conventional synthetic films with the advantages that they reduce environmental pollution and food safety issues.…”