Wan-Shin Jo

Quality Change of Apple Slices Coated with Aloe vera Gel during Storage

Fresh-cut apples are easily susceptible to browning and microbial spoilage. In this study, an edible coating prepared from Aloe vera gel containing antibrowning solution was applied to preserve the quality of fresh-cut apples during storage. Fresh-cut apples were treated with both an Aloe vera gel and an Aloe vera gel containing 0.5% cysteine and then stored at 4 °C for 16 d. The color, firmness, weight loss, soluble solid content, titratable acidity, microbial analysis, and sensory evaluation were analyzed during storage. Fresh-cut apples coated with the Aloe vera gel showed delayed browning and reduced weight loss and softening compared to the control. The Aloe vera gel coating was also effective in reducing the populations of the total aerobic bacteria and yeast and molds. In particular, Aloe vera gel containing 0.5% cysteine was most effective in delaying browning and the reduction of microbial populations among the treatments. These results suggest that an Aloe vera gel coating can be used for maintaining the quality of fresh-cut apples.

Physical properties and antimicrobial activities of a persimmon peel/red algae composite film containing grapefruit seed extract

As a by-product of dried persimmon production, persimmon peel (PP) can be utilized as an edible film base material. In this study, PP/red algae (RA) composite films were prepared, and their physical properties were determined. Among the PP composite films, the 4% PP/1% RA composite film had the best physical properties (7.31 MPa, 8.16%, and 4.99 ng m/m2s Pa for tensile strength, elongation at break, and water vapor permeability, respectively). The optical property of the PP composite film was desirable because the color of the film had an intrinsic persimmon color. In addition, the 4% PP/1% RA composite film containing 1% grapefruit seed extract was prepared as an antimicrobial film. These results suggest that this PP composite film can be applied to food packaging.

Preparation of Defatted Grape Seed Meal Protein Composite Films

Defatted grape seed meal protein (DGP) was extracted, and DGP films containing various plasticizers were prepared. To improve the mechanical properties of DGP film, nanoclay or gelatin was incorporated in the film-forming solution to manufacture DGP composite films. Among the plasticizers of fructose (FRU), sucrose (SUC), and polypropylene glycol (PPG), DGP film containing a SUC : PPG ratio of 2.5:0.5 exhibited the best film-forming ability. Addition of Cloisite improved the mechanical properties of DGP film. Tensile strength (TS) and elongation at break (E) of the film containing 5% Cloisite were 1.45 MPa and 71.97%, respectively. Regarding the DGP/gelatin composite films, TS and water vapor permeability (WVP) increased with increasing gelatin amount, whereas E decreased. In particular, the DGP/gelatin (2:2) composite film exhibited 20.95 MPa TS and 12.25% E. These results suggest that the DGP film prepared from defatted grape seed meal can be used as a food packaging material.

Preparation of a cotton seed meal protein/nanoclay composite film containing carvacrol and its effect on the growth of escherichia coli O157:H7 inoculated on bacon during storage

Cottonseed meal protein (CSP) film containing nanoclay and carvacrol was prepared, and the physical properties of the film were investigated. Nanoclay (Cloisite Na+) incorporation improved mechanical properties of the CSP film. CSP film containing 3% nanoclay had tensile strength of 4.07 MPa and elongation at break of 26.37%. The optimal condition for the CSP film manufacturing was 3 g cottonseed protein, 3 g fructose, and 0.09 g Cloisite Na+ in 100 mL of film-forming solution. To inhibit the growth of pathogenic bacteria such as Escherichia coli O157:H7, CSP film containing carvacrol was prepared, and microbial growth was examined during bacon packaging and storage using the film. The antimicrobial activity of the CSP film against E. coli O157:H7 increased with increasing carvacrol concentration. After 10 d of storage, the population of E. coli O157:H7 inoculated on the bacon samples packed with the CSP film containing carvacrol decreased by 1.57 log CFU/g compared to the control. These results suggest that the CSP film containing carvacrol can be used as an antimicrobial packaging film.