Factors affecting the quality of infused fresh-cut guava in Japanese apricot syrup using vacuum infusion Panida Banjongsinsiri1, Sodsri Neamprem2, Krittalak Pasakawee1, Poonnapha Bunyaphak1, Kulthida Chalooddong1 and Louise Wicker3 Email: panida_b@tistr.or.th 1Department of Food technology, Thailand Institute of Scientific and Technological Research, Technopolis, Khlong Luang, Patthumthani, Thailand 2Department of Postharvest technology, Thailand Institute of Scientific and Technological Research, Technopolis, Khlong Luang, Patthumthani, Thailand 3Department of Food Science and Technology, University of Georgia, Athens, GA, USA RESULT Table 1 Nutritional values of infused guava with Japanese apricot syrup at different VI conditions. Abstract Vacuum infusion (VI) has been used as a pretreatment of fresh-cut produces to improve textural quality and nutrient fortification. Our objectives were to investigate the effect of VI condition and raw material characteristics on the quality of infused fresh-cut guava. Fresh guava (peeled vs. unpeeled) were cut into pieces (3x7x1cm3) immersed in Japanese apricot syrup (30°Brix), and infused by vacuum. Two VI treatments (continuous and pulsed vacuum) were carried out at 100, 200 and 300 mmHg vacuum pressure (VP) for 1-2 min, followed by atmospheric restoration for 1-2 min. Physicochemical (color, total soluble solid; TSS, pH, and total titratable acids; TTA) and textural quality as hardness and firmness including sensory evaluation of samples were determined. Whole peeled guava was used as control. Infused guavas (whole and pieces) at 300 mmHg VP had the least L value and the greatest b value, whereas vacuum time (VT) had no significantly affected on the sample color. The pH values of VI guava increased slightly and the TTA value decreased but VI treatment had no effect on TSS value. The VP was more effective in hardness of infused guava pieces than that of whole fruits. VT also had no effect on the textural quality of infused products. No significant differences on sensory quality in terms of color, flavor, texture and overall liking of VI guava were obtained. VI conditions and raw material characteristics had affected on the physicochemical and textural qualities of infused fresh-cut guava except sensory quality. There is a great potential to use VI technique to reduce the traditional process time. Nutrients Control PP 300mmHg/2:2 min UP Total energy (kcal/100g) Moisture (%) Protein (%) Ash (%) Total fat (%) Carbohydrate (%) Dietary fiber (g) Total sugar (%) Maltitol (g/ 100 g) 40.76 88.16 0.81 0.59 10.44 2.57 8.03 0.50 Vitamin A (g/100g) Vitamin E (mg/100g) Vitamin B1 (mg/100g) Vitamin B2 (mg/100g) Vitamin C (mg/100g) 1.23 0.20 0.05 0.08 45.48 Sodium (mg/100g) Calcium (mg/100g) Magnesium (mg/100g) Potassium (mg/100g) 87.30 24.17 7.81 203.87 C TSS TTA C Note: PP=peeled/plused and UP=unpeeled/plused PC=peeled/continuous, PP=peeled/plused, UC=unpeeled/continuous, UP=unpeeled/plused, C=control PC=peeled/continuous, PP=peeled/plused, UC=unpeeled/continuous, UP=unpeeled/plused, C=control Figure 1 Color (L, a, b value) of infused guava with Japanese apricot syrup at different VI conditions. Figure 2 Chemical properties (TSS, pH, TTA) of infused guava with Japanese apricot syrup at different VI conditions. Key Findings The peeled guava was more effective in hardness of infused guava pieces than that of unpeeled fruits. The VI treatment (continuous and plused) also had affected on the physicochemical, textural qualities and sensory quality of infused fresh- cut guava. Vacuum time (VT) had no significantly affected on the physicochemical, textural qualities and sensory quality of infused fresh-cut guava. VI conditions and raw material characteristics had affected on the physicochemical, textural qualities and sensory quality of infused fresh- cut guava. VI conditions and raw material characteristics had affected to increase nutritional fortification. PC=peeled/continuous, PP=peeled/plused, UC=unpeeled/continuous, UP=unpeeled/plused, C=control Hardness Firmness C Introduction Fresh-cut guava infused with Japanese apricot syrup is well-known for the Thai consumption. However, the conventional process is fairly long that could affect the textural change and physicochemical qualities. VI has been used as a pretreatment of fresh-cut produces to improve textural quality and nutrient fortification. Figure 3 Texture quality (Hardness and Firmness) of infused guava with Japanese apricot syrup at different VI conditions. C Color Flavor Objective: Our objectives were to investigate the effect of VI condition and raw material characteristics on the quality of infused fresh-cut guava. Conclusion VI conditions and raw material characteristics had affected on the physicochemical and textural quality of infused fresh-cut guava except sensory quality. There is a great potential to use VI technique to reduce the traditional process time and enrich nutrient value of other fresh-cut produce. Method Fresh guava Cut into pieces (3x7x1 cm3) Immersed in Japanese apricot syrup (30°Brix) Infused by vacuum at 100, 200 and 300 mmHg VP for 1-2 min and atmospheric restoration for 1-2 min with continuous and pulsed vacuum Analyzed Keywords: Vacuum infusion, guava, Japanese apricot syrup Acknowledgements: The authors gratefully acknowledge the Office of the National Research Council of Thailand for funding this research. PC=peeled/continuous, PP=peeled/plused, UC=unpeeled/continuous, UP=unpeeled/plused C=control References: 1.Fito P, Chiralt A, Betoret N, Gras M, Chafer M, Martinez-Monzo J, Andres A and Vidal D. Vacuum impregnation and osmotic dehydration in matrix engineering. Application in functional fresh food development. J Food Eng 2001; 49: 175-183. 2.Xie J and Zhao Y. Nutritional enrichment of fresh apple (Royal Gala) by vacuum impregnation. Int J Food Sci Nutr 2003; 54: 387-398. 3.Park S, Kodihalli I and Zhao Y. Nutritional, sensory and physicochemical properties of vitamin E-and mineral-fortified fresh-cut apples by use of vacuum impregnation. J Food Sci 2005; 70: S593-S599. 4.Gras ML, Vidal D, Betoret N, Chiralt A and Fito P. Calcium fortification of vegetables by vacuum impregnation interactions with cellular matrix. J Food Eng 2003; 56: 279-284. 5.Zhao Y and Xie J. Practical applications of vacuum impregnation in fruit and vegetable processing. Trends in Food Sci Technol 2004; 15: 434-451. 6.Andres I, Salvatori D, Chiralt A and Fito P. Vacuum impregnation viability of some fruits and vegetables. In Fito P, Chiralt A, Barat JM, Spiess WEL and Behsnilian D (eds): Osmotic dehydration and vacuum impregnation. Behsnilian 2001. 7.Mújica-Paz H, Valdez-Fragoso A, López-Malo A, Palou E and Welti-Chanes J. Impregnation properties of some fruit at vacuum pressure. J Food Eng 2002; 56: 307-314. 8.Panades G, Treto O, Fernandez C, Castro D and Nunez De Villavicencio M. Pulse vacuum osmotic dehydration of guava. Int J Food Sci Technol 1996; 2: 301:306. 9.Panades G, Chiralt A, Fito P, Rodriguez I, Nunez M, Albors A and Jimenez R. Influence of operating conditions on sensory quality of minimally processed osmotically dehydrated guava. J Food Qual 2003; 26: 91-103. Physicochemical : Color with a Minolta chroma-meter (CR-310 Series, Japan), TSS with a digital refractometer (DR-A1, Atago, Japan), pH with pH meter microprocessor and an auto-titrator (DL53, Mettler Toledo, Switzerland), TTA (AOAC, 2000) Textural quality : Hardness and Firmness with Texture Analyzer (TA.XT.plus, Stable Microsystems, Godalming, England) Sensory evaluation : The liking scores by 25-30 untrained panelists, using 9-point hedonic scale **Whole peeled guava was used as control** Figure 4 Mean consumer satisfaction on color, flavor, texture, taste and overall liking of infused guava with Japanese apricot syrup at different VI conditions. (a) (b) (c) Figure 5 Infused guava with Japanese apricot syrup at different VI conditions; (a)control, (b)peeled/continuous300/2:2, (c)unpeeled/continuous300/2:2.