Characterization of Tuna Skin Gelatin Edible Films with Various Plasticizers‐Essential Oils and Their Effect on Beef Appearance

Valorization of Yellowfin Tuna Tails: From Proteolytic Enzyme Production to Gelatin and Antioxidant Hydrolysate Extraction

This study investigates the valorization potential of yellowfin tuna (Thunnus albacares) tails to produce high-value commercial products. Firstly, the tuna tails were placed in a perforated stainless-steel cylinder, and hydraulic pressure was applied to separate the skin from the muscle in the tails. The extracted muscle was then utilized as a nitrogen source for the growth of the proteolytic enzyme producer Bacillus subtilis, while the skins were employed for gelatin extraction. The proteases from B. subtilis were partially purified and used to produce antioxidant peptides from the obtained gelatin. The gelatin formed a gel upon cooling, with gelling and melting temperatures of 16 °C and 22 °C, respectively, and a Bloom strength of approximately 160. Response Surface Methodology (RSM) was employed to determine the optimal hydrolysis conditions to achieve the highest antioxidant activity (35.96% measured as DPPH radical scavenging activity), which were 50 °C and 6.5 IU of enzyme. The findings emphasize the importance of an integrated approach to maximize the value of tuna by-products, promoting sustainability within the framework of a circular bioeconomy. Overall, these results contribute to the efficient utilization of tuna by-products, waste reduction, and enhanced economic viability of the tuna industry.

Evaluation of a Fish Gelatin-Based Edible Film Incorporated with Ficus carica L. Leaf Extract as Active Packaging

The significant concerns associated with the widespread use of petroleum-based plastic materials have prompted substantial research on and development of active food packaging materials. Even though fish gelatin-based films are appealing as active food packaging materials, they present practical production challenges. Therefore, this study aimed to develop an edible film using Ficus carica L. leaf extract (FLE), as it is affordable, accessible, and has superoxide anion radical scavenging action. This edible film was produced by adding FLE to mackerel skin gelatin at varied concentrations (2.5-10% w/w). The results showed that adding FLE to gelatin films significantly affected the tensile strength (TS), elongation at break (EAB), transmittance and transparency, solubility, water vapor permeability (WVP), antioxidant activity, and antibacterial activity. Among all the samples, the most promising result was obtained for the edible film with FLE 10%, resulting in TS, EAB, solubility, WVP, antioxidant activity, and antibacterial activity against S. aureus and E. coli results of 2.74 MPa, 372.82%, 36.20%, 3.96 × 10-11 g/msPa, 45.49%, 27.27 mm, and 25.10 mm, respectively. The study's overall findings showed that fish gelatin-based films incorporated with FLE are promising eco-friendly, biodegradable, and sustainable active packaging materials.

Physicochemical and functional characterization of gelatin edible film incorporated with fucoidan isolated from Sargassum tenerrimum

Biodegradable films were created with fish gelatin and fucoidan extracted from Sargassum tenerrimum using 30% glycerol as a plasticizer. The gelatin films were incorporated with fucoidan (2.5%, 5%, 7.5%, and 10%), respectively. Results presented that the average thickness of films ranged from 0.12 to 0.147 mm. Tensile strength (TS) was decreased from 29.27 to 3.46 MPa by adding the fucoidan except for the gelatin/fucoidan 10% (5.35 MPa) sample. The results showed that the physical characteristics (the contact angle (Ɵ), water solubility, opacity, and moisture content) of the films significantly changed depending on different fucoidan concentrations. FTIR and SEM analysis confirmed the interaction of fucoidan with gelatin in the composite film. Furthermore, adding 10% fucoidan showed high DPPH radical scavenging activity (65%) than other treatments. Therefore, incorporation of fucoidan extracted from brown algae (Sargassum tenerrimum) with fish gelatin films improved thermal stability, anti-oxidative, and antibacterial characteristics in addition to enhanced mechanical and protective properties, to be used as a bioactive edible film in the food packaging industry.

Development of Edible Composite Film from Fish Gelatin-Pectin Incorporated with Lemongrass Essential Oil and Its Application in Chicken Meat

One of the greatest challenges encountered by the food industry is the loss of quality of food products during storage, especially perishable foods such as chicken breast, which eventually adds to the waste. Edible films are known as a potential alternative to maintain food quality and also improve shelf life by delaying the microbial spoilage and providing moisture and gas barrier properties. Developments in edible films from biopolymer composites such as fish gelatin, pectin and essential oils have great potential and promising results in enhancing the shelf life of food products. This study was conducted to determine the effect of adding pectin and lemongrass essential oil on the properties of gelatin film and its application to preserve the quality of chicken breast. In this study, the fish skin gelatin and pectin were used with various compositions (100:0; 75:25; 50:50%), with and without the addition of lemongrass essential oil to develop edible films by a casting method. The results showed that the fish gelatin-pectin with the addition of essential oils caused a significant influence on several physicochemical properties such as the thickness, transmittance, transparency, water content, tensile strength, elongation at break and also antioxidant activity (p < 0.05). The antibacterial activity evaluation showed that edible film from a biocomposite of gelatin-pectin (75:25 and 50:50) with the addition of essential oil had an inhibitory effect on Salmonella. The biocomposite of the edible film made from gelatin-pectin and the addition of lemongrass essential oil have the potential to be developed as a food packaging material, especially for perishable food. Based on the result of the application of edible film to chicken breast, it also could maintain the quality of chicken breast during storage.

Development of Composite Edible Coating from Gelatin-Pectin Incorporated Garlic Essential Oil on Physicochemical Characteristics of Red Chili (Capsicum annnum L.)

Red chili is a climacteric fruit that still undergoes respiration after harvest. During storage, it is susceptible to mechanical, physical, and physiological damage and decay incidence, therefore a method is needed to protect it so that the quality losses can be minimized. One way this can be achieved is by applying edible coatings that can be made from hydrocolloids, lipids, or composites of both, in addition to antimicrobial agents that can also be added to inhibit microbial growth. In this study, we detail the application of an edible coating made of gelatin composite from tilapia fish skin, which has a transparent color and good barrier properties against O₂, CO₂, and lipids. To increase its physicochemical and functional qualities, it must be modified by adding composite elements such as pectin as well as hydrophobic ingredients such as garlic essential oil. This study was conducted to determine the effect of a gelatin-pectin composite edible coating (75:25, 50:50, 25:75), which was incorporated with garlic essential oil (2% and 3%) on the physicochemical properties of red chili at room temperature (±29 °C), RH ± 69%) for 14 days. The best treatment was the 50-50% pectin-gelatin composite, which was incorporated with garlic essential oil with a concentration of 2 and 3%. This treatment provided a protective effect against changes in several physicochemical properties: inhibiting weight loss of 36.36 and 37.03%, softening of texture by 0.547 and 0.539 kg/84 mm², maintaining acidity of 0.0087 and 0.0081%, maintaining vitamin C content of 2.237 and 2.349 mg/gr, anti-oxidant activity (IC₅₀) 546.587 and 524.907; it also provided a protective effect on chili colors changing to red, and retains better total dissolved solid values.

Development of Edible Coating from Gelatin Composites with the Addition of Black Tea Extract (Camellia sinensis) on Minimally Processed Watermelon (Citrullus lanatus)

The purpose of this research was to determine the effect of composite fish gelatin–chitosan edible coatings enriched with black tea extract on the physical, chemical, and fungal decay properties of minimally processed watermelons stored at ±4 °C for 13 days. In this study, tuna skin gelatin was extracted and used to prepare edible coating solutions which comprised 4% gelatin, 2% chitosan, 2% calcium lactate, 2% glycerol, and black tea extract (0%; 0.25%; 0.50%; 0.75%; 1%). The samples were coated using the layer-by-layer dipping technique. This study showed that composite fish gelatin–chitosan edible coating enriched with black tea extract maintained and improved weight loss, texture (hardness), color, pH, and total soluble solid antioxidant activity and prevented fungal decay on minimally processed watermelons stored at ±4 °C for 13 days. The development in this study of edible film and a coating prepared from fish gelatin–chitosan and the incorporation of black tea extract as an antioxidant or antimicrobial agent can be a new approach to preventing postharvest loss and increasing the shelf life of minimally processed watermelon.