Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: We determined the effects of juice concentrations, outdoor storage, and thermal treatment, and pH on noni juice antimicrobial activity, which may be used as an indicator for shelf-life evaluation. We conducted Accelerated Shelf Life Test (ASLT) to evaluate the degradation of antioxidant activity of noni juice during storage at 24, 35, and 45 C. The antimicrobial activity of noni juice as affected by the pH, storage, and thermal treatment was presented in the national conference "the 2012 IFT Annual Meeting, Las Vegas, Nevada". The information was also disseminated to audiences who are interested in noni juice processing and storage. Local high school students participated in the noni shelf-life research and received training in conducting experiments, collecting data, and presenting the results. The high school student presented the study and results in national and international conferences. PARTICIPANTS: Jian Yang, Project Director; Rama Gadi and Catherine Nguyen, Research assistant; Mary Rose Canlas, undergraduate student (College of Natural and Applied Sciences, University of Guam). Verlene Joseph, Aziz Sabeti, and Jahvi Bhojwani (St. Thomas Aquinas High School, Guam). TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In the antimicrobial study, we observed that one-month outdoor storage of noni juice significantly decreased the decimal reduction rate (D-value) of noni juice against E. coli 25922, indicating an increase of noni juice in antimicrobial activity. We found that the antimicrobial activity of noni juice was pH-dependent; noni juice exhibited strong antimicrobial acidity at pH3.5-4.0, significantly lost antimicrobial activity at pH 4.5, and completely lost antimicrobial activity at pH 5-7. Thermal treatment at 45C for 48 h did not significantly changed the antimicrobial activity of noni juice while the treatment at 100C for 0.5 and 4 h significantly increase the D-value of noni juice, indicating a decrease of antimicrobial activity of noni juice. The result suggested that processing and storage affected the biological quality of noni juicethe herbal dietary supplement. In the shelf life study at 24, 35, and 45 C using ASLT, unexpected results were observed. The degradation rate of antioxidant activity assayed by DPPH and ABTS assays and total phenolic assayed by FC reagent was not significantly changed at varied temperatures during storage for 2 months. The experiments need to be further confirmed.
Publications
- Yang J. and R. Gadi. 2012. Antimicrobial activity of noni (Morinda citrifolia) juice on Escherichia coli as affected by pH, thermal treatment, and storage. Abstract. The 2012 Annual IFT Meeting. Technical Program: 042-32.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: Noni (Morinda citrifolia L.) fruit juice and powder are botanical dietary supplements marketed for improving health. The safety and quality of dietary supplements is required to meet specifications for identity, purity, strength, composition, and limits on contaminants. Noni fruit contains various biologically active phytochemicals, such as flavonoids, iridoids, anthraquinones, triterpenoids, glycosides, and lignans. However, these bioactive compounds conferring purported health benefits may not be stable enough to justify the shelf-life of noni products. The objectives of this project are: (1) to identify marker compounds and/or potential indicators that can be used to determine shelf-life and control quality of noni products; (2) to determine shelf-life of noni products by stability studies using the Accelerated Shelf Life Test with identified marker compounds and/or indicators; and (3) to validate the shelf-life of commercial noni products and extend shelf-life of noni products under various storage conditions. To achieve the project objectives, we purchased chemicals, supplies, and equipment and conducted preliminary experiments during the first year. We identified key marker compounds scopletin, rutin, and quercetin in noni juice using HPLC analysis and quantified total flavonoids, total anthroquinones, and total triterpenoids using spectrometric methods. With the aerobic plate count, we tested noni antimicrobial activity as an indicator to determine the shelf life or the strength of noni juice. We also tested rapid antimicrobial methods to determine the shelf life of noni juice using tetrazolium reduction assays with reagents MTT and INT and optical density reading. In addition, we conducted a preliminary experiment of Accelerated Shelf Life Test at 50 C to evaluate the degradation of noni quality indicators. PARTICIPANTS: Jian Yang, Project Director, College of Natural and Applied Sciences, University of Guam; supervising and managing the project. Rama Gadi, Research Assistant, College of Natural and Applied Sciences, University of Guam; conducting research experiments. Scot C. Nelson, Collaborator, University of Hawaii at Manoa; editing extension educational material. James Stith, Collaborator, JC Noni, Santa Rita, Guam; providing noni fruit. Hisamitsu Hamamoto, Collaborator, Tropical Fruit World, Tamuning, Guam; providing noni fruit. Christina Nguyen, Ian Iriarte, James Cruz, and Marlena Vergara, Undergraduate Students, College of Natural and Applied Sciences, University of Guam; conducting experiments. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
With the aerobic plate count method, fresh noni juice at concentration of 20% reduced more than 6 log CFU/mL of E. coli 25922 after treatment in TSB media at 37 C for 2 hours. The D-value of 20% noni juice against E. coli 25922 was about 22 minutes. The antimicrobial activity of noni juice was pH dependent, decreasing with an increase in pH value. Noni juice lost the antimicrobial activity at pH 7.0. With the MTT and INT reduction assays and optical density reading, noni juice at concentration of 5% enhanced the growth of E. coli 25922 in TSB media at 37 C compared to the control; noni juice at concentration of 50% completely inhibited the growth of E. coli 25922. Further experiments were needed to verify if the rapid methods with reagents MTT and INT are effective to evaluate the shelf life of noni juice. The aerobic plate count method exhibited a potential for determining the shelf life or the strength of stored noni juice.
Publications
- Yang, J. 2011. Making Fresh Noni (Lada) Juice at Home. Guam Cooperative Extension Service, University of Guam.
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