Fundamental Research Grant Scheme Phase1 (2023)
Research Title:
Red Palm Olein – Mulberry Leaf Extract Emulsion as an Antioxidant, Anti-inflammation and Anti-diabetic Regimen: Investigation on the Effect of Emulsification Conditions and Impacts on in-vitro Gastrointestinal Digestion
Principal Investigator:
Assoc. Prof. Ts. Dr. Tang Pei Ling (TAR UMT, FOAS)
Co-researchers:
Assist. Prof. Dr. Tan Phui Yee (TAR UMT, FOAS)
Dr. Yew Peng Nian (TAR UMT)
Assoc. Prof. Dr. Khairiah binti Badri (UKM)
Prof. Ts. Dr. Wan Aida binti Wan Mustapha (UKM)
Project Summary:
Red palm olein (RPO) is a recognized nutritious ingredient due to its high content of carotenes and tocols. Previous studies have revealed that its high antioxidant activity effectively relieves diabetes conditions. Unfortunately, its oxidative and thermal instability during processing restricts its applications. This study proposes the development of a stable and nutrient-dense emulsion of RPO with mulberry leaf extract (MLE). MLE, rich in phytochemicals, is known for its prominent anti-diabetic activity. The phytochemicals in MLE are expected to enrich the nutritional value of RPO while stabilizing the emulsion.
Emulsification has previously been proven to simultaneously improve the chemical stability of bioactive compounds and the physical stability of the emulsion. In this study, different formulations of emulsions (RPO-based versus MLE-based) were prepared using different emulsifiers (a combination of Tween 20 and Span 20). The effect of emulsion formulation and type of emulsifier on the physical, physicochemical, chemical, and bioactive (antioxidant, anti-inflammatory, anti-diabetic) properties of the RPO – MLE emulsion were investigated. The correlations among the physicochemical, chemical, and bioactive properties of RPO-MLE were also determined. Additionally, the synergistic bioactive properties in RPO-MLE were investigated by comparing it to RPO and MLE individually. Lastly, the emulsion undergoing in-vitro digestion to determine the effects of RPO – MLE on high-carbohydrate and high-fat digestions, as these diets are prohibited for diabetic patients.
This study demonstrated that the anti-diabetic activity of MLE was enhanced when cellulase pretreatment was conducted prior to ultrasound extraction. Additionally, lactic acid bacteria fermentation using Lactiplantibacillus plantarum TAR 4 significantly enhanced the antioxidant activity of MLE. Combining RPO with MLE produced MLE – RPO emulsion that exhibited the bioactive properties of both RPO and MLE. Compared to MLE, RPO exhibited stronger anti-inflammatory activity due to its high carotene content, whereas MLE showed prominent anti-diabetic properties due to its high 1-deoxynojirimycin (1-DNJ) content. Therefore, both RPO-based (water-in-oil) and MLE-based (oil-in-water) emulsions displayed their respective strengths and weaknesses. The RPO-based emulsion exhibited higher antioxidant and anti-inflammatory activities than the MLE-based emulsion, while the latter showed more prominent anti-diabetic activity.
After formulation optimization, a mixed emulsifier consisting of Tween 20 and Span 20 was required to produce a stable MLE-based emulsion, whereas only single emulsifier Tween 20 was needed for the RPO-based emulsion. Through process optimization, both emulsions produced were in nano forms, with particle sizes below 10 nm. Comparatively, the RPO-based nanoemulsion was more stable than the MLE-based nanoemulsion. However, the high viscosity of the RPO-based nanoemulsion may restrict its downstream applications. Lastly, the study also demonstrated that the emulsion composed of MLE and RPO significantly restricted sugar release and fat oxidation during digestion.
This project provides valuable insight into how the interplay between bioactive compounds and emulsion composition affects the functionality of functional ingredients.
Impact:
Academia – Provide a deeper understanding of how emulsification and bioactive compounds interact to enhance the stability and functionality of functional foods. This finding contributes significantly to the body of knowledge regarding the formulation of stable emulsions that retain high bioactivity.
Social – By developing a stable and nutrient-dense MLE-RPO nanoemulsion, the research offers a novel approach to managing diabetes through dietary interventions. The MLE-RPO has the potential to be used as a functional food ingredient that can support better health condition for diabetic individuals.
Industry – The study provides valuable insights into the formulation and stabilization of emulsions, which can be applied in the food and nutraceutical industries. The optimized nanoemulsions present new opportunities for developing innovative products with enhanced bioactivities and extended shelf life, thus meeting consumer demands for health-enhancing foods.
Economy – By improving the extraction efficiency of the MLE production, manufacturers can reduce waste, thereby lowering costs and increasing profitability.
Environment – The study focuses on the use of natural ingredients, RPO and MLE, aligns with sustainable practices in food production. The research supports environmentally friendly approaches to food manufacturing by adopting enzyme, fermentation and ultrasound technologies.
Publication:
Journal:
Pei Ling Tang, Sin Ru Gan, Wan Aida Wan Mustapha. 2024. Exploring potential of jicama and mulberry leaf extracts as the hypoglycemic additive in rice simulated in-vitro digestion. Journal of Food Measurement and Characterization 18, 845 – 870. DOI: https://doi.org/10.1007/s11694-023-02245-4
Conference proceedings:
Pei Ling Tang, Han Hong Teo, Wan Aida Wan Mustapha, Phui Yee Tan, Khairiah Badri. 2024. Interplay Effect Between Mulberry Leaf Extract and Red Palm Oil on the Physicochemical Characteristics and Antioxidant Activity of O/W and W/O Nanoemulsions. In Proceedings of the International Applied Biology Conference 2024: Sustainability through Applied Biology: Nurturing Ideas, Innovations and Life Solutions. 7 – 9 June 2024. Jen Penang Georgetown by Shangri-La., Penang, Malaysia.
Han Hong Teo, Pei Ling Tang, Wan Aida Wan Mustapha. 2023. Effects of Mixed Emulsifier (Tween 20 and Span 20) on the Physicochemical Properties and the Stability of Mulberry Leaf Extract – Red Palm Olein (MLE – RPO) Emulsion. In Proceedings of the 17th ASEAN Food Conference 2023: Future of Food in ASEAN: What’s Next? 24 – 27 October 2023. Borneo Convention Centre, Kuching, Sarawak, Malaysia.
Conference abstract book:
Huei Chin Chew, Phui Yee Tan, Pei Ling Tang. 2022. Cellulase Pretreatment to Enhance Antioxidant, Anti-inflammatory and Hypoglycemic Activities of Mulberry Leaf Extract. In abstract book of International Applied Biology Conference 2022: Sustainable Development Goals through Applied Biology. 3 – 5 June 2022. Hatten Hotel, Melaka, Malaysia.