Development of Mugwort essential oil supplemented chitosan/gelatin coatings for enhancing quality and microbiological safety of chicken meat = 닭고기 품질 및 미생물학적 안전성 향상을 위한 쑥 에센셜 오일 첨가 키토산/젤라틴 코팅 개발

국문 초록 (Abstract)

저장 및 유통 과정에서의 신선도 보존은 닭고기의 품질과 안전성 유지에 필수적이다. 쑥은 다양한 생리활성 화합물을 풍부하게 함유하고 있음에도 불구하고, 닭고기의 천연 보존제로 활용된 사례는 보고되지 않았다. 따라서 본 연구에서는 키토산/젤라틴 코팅 용액에 쑥 에센셜 오일(MEO)을 첨가하여 닭가슴살에 적용했을 때의 항균 및 항산화 특성을 평가하고자 하였다. 코팅 용액의 점도, 코팅률, 유지율 및 미세구조를 고려하여 키토산(1.5%, v/v)과 젤라틴(3%, v/v)을 혼합한 최적의 기초 코팅 용액을 확립하였으며, 여기에 MEO (0%, 0.5%, 1%, v/v)를 첨가하였다. 최적화된 MEO 함유 식용 코팅을 닭가슴살에 적용하여 4°C에서 14일간 저장하며 품질 변화를 평가하였다. 그 결과, MEO/키토산/젤라틴 코팅 용액은 닭가슴살 내 총균수, 대장균군, 효모 및 곰팡이, Listeria monocytogenes, Salmonella Enteritidis에 대해 유의적인 항균 활성을 나타냈다. 또한, 해당 코팅을 적용한 닭가슴살은 비코팅 시료에 비해 색도, pH, 단백질 분해, 지질 산화, 전단력 및 육즙 손실에서 초기 품질을 효과적으로 유지하였다. 특히, MEO의 첨가는 항균 활성과 초기 품질 유지 효과를 더욱 향상시켰다. 이러한 보존 효과는 MEO에 풍부하게 존재하는 테르페노이드 및 플라보노이드 화합물에 기인한 것으로 판단된다. 결론적으로, MEO 첨가는 키토산/젤라틴 식용 코팅의 보존 특성을 현저히 개선하고 닭가슴살의 신선도를 효과적으로 유지하였음을 확인하였다.

다국어 초록 (Multilingual Abstract)

Preservation of freshness during storage and distribution is essential for maintaining the quality and safety of chicken meats. Mugwort (Artemisia vulgaris), known for its abundance of bioactive compounds, has not yet been used as a natural preservative for chicken meats. Therefore, we aimed to evaluate mugwort essential oil (MEO) as an edible coating substance by incorporating it into a chitosan/gelatin coating solution and assessing its antimicrobial and antioxidant properties on chicken breasts. The base coating solution was optimized by mixing chitosan (1.5%, v/v) and gelatin (3%, v/v), considering its viscosity, coating rate, retention rate, and microstructure. MEO (0%, 0.5%, and 1%, v/v) was added to the optimized chitosan/gelatin edible coating solutions. The optimized edible coating containing MEO was applied to chicken breasts for storage tests (14 days at 4°C). The MEO/chitosan/gelatin coating solutions showed significant antimicrobial activity, including total bacterial counts, coliforms, yeasts/molds, Listeria monocytogenes and Salmonella Enteritidis in chicken breasts. The MEO/chitosan/gelatin-coated chicken breasts maintained their initial physicochemical quality in terms of color, pH, protein degradation, lipid oxidation, shear force, and drip loss compared to the uncoated samples. Overall, the incorporation of MEO further enhanced the antimicrobial activity and the maintenance of the initial quality. The preservation ability of the MEO/chitosan/ gelatin coating solutions may be attributed to its abundant terpenoid and flavonoid compounds. In conclusion, the addition of MEO significantly improved the preservative qualities of the chitosan/gelatin edible coating and effectively maintained the freshness of chicken breast.

목차 (Table of Contents)

• List of Tables ⅲ
• List of Figures ⅳ
• Abstract ⅴ
• 1. Introduction 1
• 2. Materials and methods 4
• 2.1. Materials and bacterial strains 4
• 2.2. Liquid chromatography-quadrupole time-of-flight-tandem mass spectrometry (LC-QTOF/MS/MS) analysis of mugwort essential oil 4
• 2.3. Preparation of chitosan/gelatin edible coating solution 5
• 2.4. Characteristics of chitosan/gelatin edible coating 6
• 2.4.1. Viscosity and coating rate 6
• 2.4.2. Nile red staining 7
• 2.4.3. Retention rate 7
• 2.4.4. Fourier transform infrared spectroscopy (FT-IR) 8
• 2.4.5. Field emission scanning electron microscopy (FE-SEM) 8
• 2.5. Preparation of chicken breast sample 8
• 2.6. Characteristics of chicken breast during storage 9
• 2.6.1. Microorganism analysis 9
• 2.6.2. Color and pH 10
• 2.6.3. Volatile basic nitrogen (VBN) 10
• 2.6.4. Thiobarbituric acid reactive substances (TBARS) 11
• 2.6.5. Shear force 11
• 2.6.6. Drip loss 12
• 2.7. Statistical analysis 12
• 3. Results and discussion 13
• 3.1. Optimization of the ratio of chitosan/gelatin edible coating solution 13
• 3.1.1. Viscosity, coating rate, and retention rate of base edible coating solution 13
• 3.1.2. Microstructure analyses of base edible coating solution 16
• 3.2. Evaluation of chicken breast qualities during storage 19
• 3.2.1. Microorganism analyses of chicken breast 19
• 3.2.2. Color of chicken breast 26
• 3.2.3. pH, VBN, TBARS value of chicken breast 29
• 3.2.4. Shear force and drip loss of chicken breast 32
• 4. Conclusion 35
• References 36
• Appendix 45
• Abstract (in Korean) 49