The Effect of Acidic and Alkaline pH on the Physico-Mechanical Properties of Surimi-Based Edible Films Incorporated with Green Tea Extract

Abstract

The effects of green tea extract (GTE) at acidic and alkaline pH (pH 3 and 11, respectively) on the physico-mechanical, thermal, and water transmission properties of silver carp surimi-based edible films were investigated. Incorporation of GTE significantly (p < 0.05) reduced elongation at break (EAB) but improved tensile strength (TS). Significant (p < 0.05) decreases in the solubility of films and water vapor permeability (WVP) were also perceived in GTE-containing films. Transparency and color were also affected, depending upon the concentration and pH. Films prepared at an acidic pH demonstrated significantly (p < 0.05) improved WVP, transparency, solubility, and thermal stability compared to those prepared at an alkaline pH. The protein pattern of films revealed a strong interaction between phenolic compounds of GTE and surimi proteins as evidenced by the presence of a myosin heavy chain (MCH) at the top of the gel. Generally, the addition of GTE at an acidic pH had significantly (p < 0.05) greater impact on film properties than at an alkaline pH and could offer great potential for surimi protein-based edible films with improved properties.

A Narrative Review on Rice Proteins: Current Scenario and Food Industrial Application

“…Phenolic interaction can change the structure and functional properties of the protein. Source of protein, pH, surface properties of the protein, amino acid composition, number of hydroxyl groups, isoelectric points, temperature, the type of structure, and the type of interaction are the factors that affect protein-phenolic interaction [ 62 , 63 ]. The variation in pH denatures the protein’s native structure to expose the hydrophobic groups.…”

Green Tea Extract Enrichment: Mechanical and Physicochemical Properties Improvement of Rice Starch-Pectin Composite Film

“…Natural antioxidants and antimicrobial agents are alternatives to synthetic food preservatives to avoid potential health concerns and a strict regulation associated with the usage of the artificial food preservatives [31,33]. The inclusion of green tea extract (GTE) has been extensively studied to improve the functional properties of various film bases, for example, polypropylene [34], agar-gelatin [35], gelatin [36], surimi [37], and starch-LLDPE [38], poly(vinyl alcohol) (PVA) [39]. Green tea (Camellia sinensis L.), a non-fermented tea, is rich in polyphenolic compounds, especially catechins.…”

The Water Content, Solubility, and Optical Properties of Whey-Gelatin Multilayer Films Enriched with Green Tea Powder

“…Kandungan senyawa fenolik teh hijau jauh lebih tinggi, tidak hanya mempertahankan struktur aslinya tetapi juga komposisi keseluruhannya (Robalo et al, 2022). Inklusi teh hijau telah banyak dipelajari untuk meningkatkan sifat fungsional berbagai basis film diantaranya menggunakan gelatin (Maroufi et al, 2020), agar-agar (Giménez et al, 2013), pati-LLDPE (Panrong et al, 2019 dan surimi (Munir et al, 2020). Film edible film biopolimer yang diperkaya teh hijau tidak hanya dapat memperpanjang masa simpan dan meningkatkan kualitas produk makanan, tetapi juga memiliki potensi manfaat kesehatan bagi konsumen.…”

“…Hasil ini sesuai dengan penelitian (Guo et al, 2014) yang menggunakan xanthan gum dan xantham gum teroksidasi dimana dapat mengurangi kapasitas pengikatan air dan menurunkan kelarutan film . Interaksi antara protein whey-gelatin dan senyawa fenolik yang terkandung dalam bubuk teh hijau dapat menguntungkan untuk pembentukan struktur film multilayer yang lebih padat sehingga dapat menghasilkan daya tarik air yang lebih rendah (Munir et al, 2020). Secara umum semua film multilayer yang dihasilkan dalam penelitian ini menunjukkan nilai kelarutan mendekati atau dibawah 50%, sehingga sangat cocok untuk aplikasi pengemas pangan berlemak (Valdés et al, 2021).…”