Recipient Organization
UNIVERSITY OF GUAM UOG STATION
(N/A)
MANGILAO,GU 96913
Performing Department
Experiment Station
Non Technical Summary
Calamansi (Citrus microcarpa) is a unique citrus on Guam and in Pacific islands. Many residents have calamansi trees at backyard. The tree produces fruit at peak season from March to July. People use calamansi often as an ingredient for seasoning or preparing various foods. Citrus is a rich source of vitamins, minerals, and phytochemicals. Citrus peels contain more phytochemicals than citrus juice. Especially, the citrus polymethoxylated flavonoids, such as nobiletin, tangeretin, and sinesetin, in peels exhibit biological properties including anticancer, anti-bacterial, antiviral, anti-inflammatory, and anti-diabetic activity. Unfortunately, citrus peels are discarded as a waste either in food industry or at home. The objectives of this project are to: (1) Determine the biological properties and bioactive components of calamansi peels; (2) Develop calamansi-peel functional ingredients with high biological properties; and (3) Determine food quality, safety, and functional properties of selected foods incorporated with calamansi-peel functional ingredients for application. The significance of the project is to explore and use the value of the underutilized citrus 'calamansi' grown on Guam. The developed calamansi-peel functional ingredients may potentially promote calamansi production, value-added food processing, and agriculture economy as well as improving critical health issues in the community of Guam.
Animal Health Component
30%
Research Effort Categories
Basic
35%
Applied
30%
Developmental
35%
Goals / Objectives
The goal of project is to explore and use the value of the underutilized citrus 'calamansi' grown on Guam and develop calamansi-peel functional ingredients for promoting calamansi production, value-added food processing, and agriculture economy as well as improvement of critical health issues in the community of Guam. The objectives of this project are to: (1) Determine the biological properties and bioactive components of calamansi peels; (2) Develop calamansi-peel functional ingredients with high biological properties; and (3) Determine food quality, safety, and functional properties of selected foods incorporated with calamansi-peel functional ingredients for application.
Project Methods
The methods used in the project include the following:Materials Calamansi fruit in different maturity (green, green-orange, and orange) will be collected from the trees at various seasons (January, April, July, and October) on Guam.Calamansi fruit will be cleaned, sorted, and cut into half. After seeds are removed, the calamansi peel will be freeze-dried or air-dried. The dried calamansi peels will be milled into powder, packaged in frozen food bags, and stored in refrigerator for further use.Extraction The calamansi peel powder will be extracted with various solvents (water, ethanol, methanol, acetone, and diethyl either) on a shaker for 24 hours at room temperature. The solvents in the extracts will be removed or concentrated using rotary evaporator under vacuum. The concentrated extracts will be freeze-dried. The freeze-dried peel extracts will be used to determine bioactive components and biological properties. Based on the results, further separation and purification may be conducted to isolate bioactive compounds by High Performance Liquid Chromatography (HPLC) system.Analysis of bioactive components Total phenolic content of the freeze-dried peel extract will be analyzed using Folin-Ciocalteu reagents and expressed as mg of gallic acid equivalents per mg of calamansi extracts.Total flavonoid content will be determined using aluminum chloride and expressed as mg of quercetin equivalents per mg of calamansi extracts.The total, insoluble, and soluble dietary fibers contents (%) of calamansi-peel extract will be estimated by an enzymatic-gravimetric method.Analysis of biological properties Antioxidant activity of calamansi-peel extract will be determined using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. The inhibition (%) of DPPH free radicals will be calculated and expressed as mmol Trolox equivalent per mg of calamansi-peel extract.Antimicrobial activity of calamansi-peel extracts will be determined using non-pathogenic indicator strains of E. coli and L. innocua. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of calamansi extracts against E. coli and L. innocua will be evaluated for antimicrobial activity of calamansi-peel extracts.Antidiabetic activity of calamansi-peel extracts will be analyzed by a-amylase inhibition assay and a-glucosidase inhibition assay. The inhibition (%) of hydrolyzing carbohydrates (starch and maltose) will be calculated and expressed as antidiabetic activity of calamansi extract.Development of functional foods Based on the above experiment results, the calamansi-peel extract containing high bioactive components and biological properties will be selected to make the calamansi functional ingredients. The stability and solubility of the functional ingredients will be studied and optimized for application in foods. The functional ingredient will be incorporated in selected tropical fruit drink, smoothie, and yogurt to make functional foods for benefiting human health. The total phenolic content, total flavonoid content, antioxidant activity, and antidiabetic activity will be determined for these developed functional foods.Prevention of lipid oxidation Fish products such as fish ball are easily oxidized. The calamansi-peel functional ingredient will be incorporated in fish ball to prevent the lipid oxidation. Peroxide value (PV) of fish ball samples will be determined by spectrophotometry method using ammonium thiocyanate and Fe(II) chemicals. The results will be expressed as milliequivalents of peroxide per kg fat and evaluated for lipid oxidation in fish ball.Enhancement of food safety Food safety is another critical issue on Guam. Calamansi-peel functional ingredient will be incorporated into chicken kalaguen and tuna poker to inhibit bacterial growth. Non-pathogenic indicator strains of E. coli and L. innocua will be first inoculated in these products; then calamansi-peel functional ingredient at various concentration will be added. After storage at room and refrigerator temperature for certain hours, the kalaguen and poke were sampled, E. coli and L. innocua and total plate count of aerobic mesophillic organisms will be numerated. The inhibition of bacterial growth will be evaluated as a food safety indicator.Sensory evaluation The color, taste, and aroma of foods are important attributes for food quality. The sensory evaluation for quality attributes and consumer acceptance will be evaluated by recruiting 30 panelists. The panelist will be asked to taste the foods and evaluate the quality of functional foods, kalaguan, and tuna poke. The color values of these products will also be determined using a color meter.Statistical analysis In the study, replications will be performed for all the experiments and assays. Experiment data will be analyzed with the software of Statistix 10 (Analytical Software) using the ANOVA multiple sample comparison. Statistically significant effect (p<0.05) will be analyzed and means will be compared by the Tukey's HSD test.To make a change in knowledge, actions, or conditions, we will deliver the knowledge and technology generated in the project to the targeted audiences through informal education at Cooperative Extension & Outreach Program and formal education at Food Science & Nutrition Program, College of Natural Life Sciences, University of Guam. The activities in the informal and formal education include workshops, laboratory instruction, practicum experiences, and formal classroom instruction.The success of the project will be mainly evaluated based on results of research experiments and efforts to deliver generated knowledge and technology. The key milestones in research experiments include: the solid data and results of bioactive components and biological properties of calamansi peel; the developed calamansi functional ingredients and their effective functional properties in food products. Statistical analysis will be performed to determine the significant difference among the collected data. The change of targeted audiences' knowledge will be evaluated in the conducted workshops or other informal education through pre- and post-tests. The change of targeted audiences' action will be evaluated through the communication and interview between the project team members and targeted audiences.