Novel Active Food Packaging Films Based on Gelatin-Sodium Alginate Containing Beetroot Peel Extract

Abstract

Currently, the exploration of natural colorants from vegetal waste has gained particular attention. Furthermore, incorporation of these natural sources into biopolymers is an encouraging environmentally friendly approach to establishing active films with biological activities for food packaging. The present study developed bioactive antioxidant films based on gelatin-sodium alginate (NaAlg) incorporated with aqueous beetroot peel extract (BPE). Firstly, the effects of combining gelatin-NaAlg and BPE at 0.25, 0.5, and 1% on the mechanical, physical, antioxidant, and antibacterial properties of the films were analyzed. With increasing BPE, mechanico-physical properties and antioxidant and anti-foodborne pathogen capacities were enhanced. Likewise, when added to gelatin-NaAlg films, BPE remarkably increased the instrumental color properties. Moreover, during 14 days of storage at 4 °C, the impact of gelatin-NaAlg coating impregnated with BPE on microbial and chemical oxidation and on the sensory characteristics of beef meat samples was periodically assessed. Interestingly, by the end of the storage, BPE at 1% limited the microbial deterioration, enhanced the instrumental color, delayed chemical oxidation, and improved sensory traits. By practicing chemometrics tools (principal component analysis and heat maps), all data provided valuable information for categorizing all samples regarding microbiological and oxidative properties, sensory features, and instrumental color. Our findings revealed the ability of gelatin-NaAlg with BPE as an antioxidant to be employed as food packaging for meat preservation.

Keywords: active packaging; beetroot extract; mechanico-physical and optical characteristics; microbial spoilage; minced beef meat; multivariate analysis; oxidative stability; shelf-life extension.

Figure 1

HPLC chromatograms corresponding to (a) Bcs (Bc1 and Bc2) and (b) Bx of the aqueous extract of beetroot peel (BPE).

Figure 1

HPLC chromatograms corresponding to (a) Bcs (Bc1 and Bc2) and (b) Bx of the aqueous extract of beetroot peel (BPE).

Figure 2

Visual aspects of (a) control (0%), (b) 1-BPE (0.25%), (c) 2-BPE (0.5%), and (d) 4-BPE (1%) films.

Figure 3

Effect of the films (control (0%), 1-BPE (0.25%), 2-BPE (0.5%), and 4-BPE (1%)) on (a) MetMb (%), (b) CC (nmol carbonyl/mg of protein), and (c) SH (mmol sulphydryl/g of protein) of raw minced meat beef stored at 4 °C for 14 days; ±: standard deviation (SD) of three replicates; a–d: mean values within all the samples not followed by a similar letter in the same column varied significantly (p < 0.05); A–E: mean values during storage not followed by a similar letter in the same line varied significantly (p < 0.05).

Figure 4

Effect of the films (control (0%), 1-BPE (0.25%), 2-BPE (0.5%), and 4-BPE (1%)) on (a) PV (meq of peroxide/Kg), (b) CD (μmol/mg of meat), and (c) TBARS (mg MDA-eq/Kg) of raw minced meat beef stored at 4 °C over 14 days; ±: standard deviation (SD) of three replicates; a–d: mean values within all the samples not followed by a similar letter in the same column varied significantly (p < 0.05); A–E: mean values during storage not followed by a similar letter in the same line varied significantly (p < 0.05).

Figure 5

Visual aspects, after 14 days of storage at 4 °C, of minced beef meat packed with (a) control (0%), (b) 1-BPE (0.25%), (c) 2-BPE (0.5%), and (d) 4-BPE (1%) films.

Figure 6

Loading plots of the two principal components (F1, F2) based on all samples (n = 20) (a) and on physicochemical, microbial growth, color, and sensorial property values of meat samples over 14 days of storage (b).

Figure 7

Heat maps of physicochemical, microbial growth, color, and sensorial property values of packaged raw meat samples on (A) day 0; (B) day 3; (C) day 7; (D) day 10; and (E) day 14 of storage.

Figure 7

Heat maps of physicochemical, microbial growth, color, and sensorial property values of packaged raw meat samples on (A) day 0; (B) day 3; (C) day 7; (D) day 10; and (E) day 14 of storage.