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2 Processing and Quality Evaluation of Chili Jam Abstract The effects of different conditions for reducing the pungency of red hot chili and the variation in the ratio of red hot chili and red bell pepper on physical and sensory properties of chili jam were studied. Results on physical analysis showed that the sugar concentration (4% and 5%w/v) and soaking time (1, 2 and 3 hrs) influenced (p < 0.05) texture and Hunter values of the product. Sensory results also revealed significant differences (p < 0.05) on the scores of appearance, color and taste attributes. n addition, a* values, ph, texture, appearance and overall acceptance of the product were affected by the difference in the ratio of red hot chili to red bell pepper (1:4, 2:3, 3:2 and 4:1). The chili jam made with the red hot chili which was soaked in 5% sugar solution for 1 hr, and composed of red hot chili and red bell pepper at the ratio 2:3, was the most acceptable product. The physical, sensory and microbiological quality of the chili jam in an opened-container after being kept at 4-5 o C for 21 days were also investigated. Significant increases (p < 0.05) in ph and total soluble solid were found, whereas the sensory results showed no statistical differences (p>0.05). Based on microbiological determination, no growth was observed throughout storage time. Keywords: Chili, Jam Processing, Pungency ntroduction Chili peppers (Capsicum spp.) are an excellent source of vitamin C and high in vitamin A, vitamin B, vitamin E, potassium and folic acid. They are cholesterol free, low in calories and believed to have many beneficial effects on health as well. Chilies are often used to spice up dishes cooking in ethnic cuisine including Mexican, ndian, Vietnamese, Arab, Spanish and Thai. Growing popularity of spicy foods has had a major impact on chili usage. Besides, the trend for reduce-fat food has contributed to the growth of using hot spices since both flavor and textures are affected when fat are removed from food (Wikipedia, 2006). There are several varieties of chili peppers and each differs in flavor and heat intensity. n general, the smaller the pepper, the hotter it is. Chili peppers are fiery because of a pungent substance called capsaicin (8-methyl- N-vanillyl-6-nonenamide), an alkaloid substance which makes chili hot to taste and causes burning sensation to consumers (Fisher and Scott, 1997). The hotter the chili, the more capsaicin it contains. Capsaicin causes the 184

3 Õ π ÿ À À å body to release endorphins which can give a person a feeling of well-being and pleasure (George Meteljan Foundation, 2006). t also stimulates nerve endings to release mediators, chemical substances that inform the brain about pain or inflammation. n addition, it was found to act as an antioxidant and may help prevent bacterial infections because of its mildly antibacterial properties. Chilies are now globally used in foods both for its coloring properties and health benefits. Because of the burning sensation, the presence of chili maybe limits consumer acceptability of the product, especially in desserts which are widespread in Western countries. As sugar are known to have a moderating effect on the hot flavor of capsaicin (Wikipedia, 2006), the pre-treatment with sugar at the proper condition appears to be an important means of reducing the pungency of chili while helping to minimize the burning sensation. The objective of this study was to formulate chili jam in which red hot chili (Capsicum chinense Jacq.) in combination with red bell pepper (Capsicum annuum Linn.) are used as both the main ingredients and colorants. The optimum condition for reducing the pungency of red hot chili and the proper ratio of red hot chili to red bell pepper used in jam processing were determined based on physical and sensory properties of the product. The microbiological quality of the chili jam during refrigerated storage in an opened-container was also investigated. Materials and Methods Materials Red hot chilies (Capsicum chinense Jacq.) and red bell peppers (Capsicum annuum Linn.) were purchased from the local market. Pectin (grade 150), citric acid and glucose syrup were obtained from Thai Food and Chemical Co., Ltd. Preparation of Red Hot Chili Puree The manual operation of washing and defecting removing for red hot chilies was initially done. The seeded red hot chilies were soaked in sugar solution at two concentrations (4% and 5% w/v) for 1, 2 and 3 hr. After pouring out the sugar solution, the hydrated chilies were blended with water (1:2 w/w) for 40 sec using a Waring blender. Processing of Chili Jam The formulation of chili jam is given in Table 1. The chili jam was prepared by mixing of the red hot chili puree with two volume of water in a stainless pot. After adding of chopped red bell pepper (the ratio of red hot chili to red bell pepper was 2:3), the mixture was heated to o C. Pectin and sugar 185

4 Processing and Quality Evaluation of Chili Jam (1:10w/w) were mixed thoroughly to avoid clumping before adding to the mixture. The mixture was further heated for 2 min with constant stirring and the rest of sugar and glucose syrup were then added. When the total soluble solid of the mixture was reached at o Brix, citric acid and lemon juice were added. The mixture was cooked for approximately 10 min with constant stirring or until the mixture had a jam-like consistency. The jam was hotfilled (70-75 o C) into sterile containers, allowed to cool at room temperature (28-30 o C) prior to further analysis. Table 1 The formulation of chili jam ngredients Amount (% w/w) Chili (red hot chili puree and red bell pepper) Sugar Glucose syrup Pectin (grade 150) 0.50 Citric acid 0.50 Lemon juice 1.00 Water Experimental Design The optimum condition for the preparation of red hot chili puree and the proper ratio of red hot chili to red bell pepper used in jam processing were determined on the basis of physical and sensory analysis. Also, accelerated shelf life study was designed to evaluate the microbiological quality of the product. The data of physical analysis was statistically examined by a completely randomized design (CRD), while sensory data was conducted using randomized complete block design (RCBD). Physical Analysis Total soluble solid (TSS). This value expressed as o Brix of jam was measured by using a refractometer. ph. The jam (10 g) was homogenized in 100 ml water. The ph was measured by using a ph-meter (model 320, Mettler-Toledo Ltd., Essex, UK) according to AOAC (1990) method. Color. The jam color was determined by using a Hunter Lab digital colorimeter model D25 M (Hunter Associates Laboratory, Reston, VA). Values for L* (lightness), a* 186

5 Õ π ÿ À À å (redness/greenness) and b* (yellowness/ blueness) were recorded for 5 samples per batch. Texture. The Lloyd texture analyzer model LRX (Lloyd instruments, Hampshire, UK) with 1000 N load cell, crosshead speed 250 mm/min was used for texture determination. Five samples were evaluated for peak force (N) using a jam-type test cell. All analyses were performed in triplicate. Sensory Evaluation Twenty-four untrained panelists were chosen from students of the Thai Chamber of Commerce (UTCC) based on their interest as participants and their jam familiarity. Each jam treatment (coded with random 3-digit number) was evaluated for overall acceptability with regard to appearance, color, flavor, texture and taste attributes by using a 9-point hedonic scale test (1 = extremely dislike, 9 = extremely like). The chili jam was served on an unsalted cracker (3 g/sample) and panelists were instructed to cleanse their palates with distilled water before tasting the samples and anytime during the test as needed. All tests were held at the UTCC sensory laboratory within a partitioned booth. Three replicates were performed for sensory quality evaluation. Microbiological Determination Samples of 10 g were aseptically weighed and placed in a Stomacher bag containing 90 ml of sterile 0.1% peptone (Difco) diluent and pummeled for 1 min with a Stomacher-400 (Tekmar Company, Cin cinnati, OH). Homogenate was then diluted serially to obtain proper dilution for microbiological tests at days 1, 7, 14 and 21 during storage at 4-5 o C. The total plate count (APC) was determined using aerobic count plates (3M Petrifilm TM ) with incubation at 35 o C for 48 hr. The yeast and mold were enumerated using Y&M count plates (3M Petrifilm TM ) after storing at 25 o C for 5 days. Statistical Analysis Data were analyzed by statistical Package SPSS for window version An analysis of variance (ANOVA) was used to evaluate significant difference at level of 5% (p < 0.05). f a significant F-test was noted, treatment means were separated using the Duncanûs New Multiple Range Test; DMRT (Cochran and Cox, 1992). Results and Discussion The optimum condition for the preparation of red hot chili puree n Table 2, the data showed that sugar concentration and soaking time for red hot chili had a significant effect (p<0.05) on 187

6 Processing and Quality Evaluation of Chili Jam Hunter values (L*, a*, b*) and texture of the chili jam, whereas ph was unaffected. The lightness of chili jam tended to decrease when red hot chili was soaked in 4% sugar solution for 1 hr up to 3 hrs, while redness and yellowness increased with the increasing soaking time. The used of 5% sugar solution resulted in significant higher (p<0.05) a* and b* values but lower L* values when compared with the treatments at the same soaking time. As in the case of texture, the data exhibited a significant increase (p < 0.05) in firmness as the soaking time increased, but slightly reduced at higher concentration of sugar solution in relation to other treatments at the same soaking time. Sensory results of the chili jam are presented in Table 3. The analysis of variance revealed that appearance, color and taste attributes were significantly affected (p < 0.05) by different conditions used for preparing red hot chili puree. On the contrary, the sensory scores of flavor, texture and overall acceptance showed no significant differences (p > 0.05) among all treatments. Correlations between the sensory attributes were determined (data not shown) and there was satisfactory correlation between overall acceptance and texture (R 2 = 0.860, p<0.05). Also, overall acceptance showed greatly correlated with taste attribute (R 2 = 0.938, p<0.01). t was observed that the treatment with 5% sugar solution and soaking time 1 hr, had the highest score in all attributes, thus this condition was chosen for chili jam processing in further study. Table 2 Effects of sugar concentration and soaking time on physical properties of chili jam Sugar Soaking ph ns Texture CE Color value concentration time (N) L* a* b* (% w/v) (hr) c a b b ab b b b a c a a c c a a bc d a ab a c a a a,b,c,d Means in the same column with different superscripts are different (p < 0.05) by DMRT. ns = non-significant. CE color values : L* = lightness (0 = black, 100 = white) a* = redness / greenness (+ = red, - = green) b* = yellowness / blueness (+ = yellow, - = blue) 188

7 Õ π ÿ À À å Table 3 Effects of sugar concentration and soaking time on sensory attributes of chili jam Sugar Soaking Sensory scores concentration time Appearance Color Flavor ns Taste Texture ns Overall (%w/v) (hr) acceptance ns ab 6.6 ab b ab 6.9 ab ab b 6.4 c ab a 7.3 a a ab 7.1 ab a ab 6.6 ab a a,b,c Means in the same column with different superscripts are different (p < 0.05) by DMRT. ns = non-significant. Based on a 9-point hedonic scale test (1 = extremely dislike, 9 = extremely like). Proper Ratio of Red Hot Chili and Red Bell Pepper for Chili Jam Processing The physical properties of chili jam made with different ratios of red hot chili and red bell pepper are shown in Table 4. t was seen that L* and b* values were no significant differences (p>0.05) while a* value, ph and texture increased (p<0.05) with the proportion of red hot chili used. A slight change in ph was possibly because of the differences in degree of solubility and the quantity of water-soluble pigments in both chilies. As expected, the a* values increased (p<0.05) with the more portion of red hot chilies as they are usually higher in color intensity than red bell peppers (Biad Chili Ltd. Co, 2006). At the same time, the red color of chili which is due to anthocyanins is affected by the changes in ph (Wikipedia, 2006). On the basis of texture, it appeared an increase (p<0.05) in firmness of chili jam as the portion of red bell pepper decreased. This was possibly because fresh red bell pepper had very thick and firm skin (James. T.Ehler, 2006). The decreased proportion of red bell pepper meant a decrease in irregular dispersion of chili in the matrix. Consequently, the jam matrix was more compact. However, the reduction (p<0.05) in firmness was detected at the ratio of 4:1. There may be several factors determining how easily a jam sets and also the jam matrix properties during processing. The high portion of hydrated red hot chili raised the moisture content of the mixture; therefore, the jam was possibly more soften than at the ratio of 3:2. 189

8 Processing and Quality Evaluation of Chili Jam Mean values of all sensory attributes are listed in Table 5. The results exhibited significant differences (p < 0.05) in the scores of appearance, texture and overall acceptance. There were no significant differences (p > 0.05) in the scores of color and flavor attributes. Considering panelistsû comments, the treatment with the highest ratio (4:1) had a slight burning sensation according to the spicy flavors and hot taste. There were positively correlations among all sensory attributes (data not shown). Overall acceptance was highly correlated with the two attributes; color (R 2 = 0.981, p < 0.01) and taste (R 2 = 0.980, p < 0.05), which also showed highly correlated (R 2 = 0.986, p < 0.01) with each other. Additionally, texture was also greatly correlated with appearance (R 2 = 0.988, p < 0.01). These results followed to the conclusion that the treatment at the ratio 2:3, which presented the highest score in all attributes, could be considered as the most acceptable product in this study. Table 4 Physical properties of chili jam made with different ratios of red hot chili and red bell pepper ph CE Color value Texture Red hot chili : Red bell pepper L*,ns a* b*,ns (N) 1: d d c 2: c c b 3: b b a 4: a a b a,b,c,d Means in the same column with different superscripts are different (p < 0.05) by DMRT. ns = non-significant. CE color values : L* = lightness (0 = black, 100 = white) a* = redness / greenness (+ = red, - = green) b* = yellowness / blueness (+ = yellow, - = blue) Table 5 Sensory scores of chili jam made with different ratios of red hot chili and red bell pepper Red hot chili : Sensory scores Red bell pepper Appearance Color ns Flavor ns Taste Texture Overall acceptance 1:4 6.9 ab b 6.7 b 6.7 b 2:3 7.4 a a 7.1 a 7.4 a 3:2 6.5 b b 6.5 b 6.9 a 4:1 6.6 b b 6.6 b 6.3 c a,b,c Means in the same column with different superscripts are different (p < 0.05) by DMRT. ns = non-significant. Based on a 9-point hedonic scale test (1 = extremely dislike, 9 = extremely like). 190

9 Õ π ÿ À À å Physical, Microbiological and Sensory Analysis of Chili Jam Table 6 showed the physical and microbiological analysis data of the chili jam (red hot chili : red bell pepper = 2:3) in an opened-container during refrigerated storage for 21 days. The TSS tended to increase and the texture improved (p<0.05) throughout the storage time. This presumably caused by the moisture loss during storage (Gajar and Badrie, 2001), so that the jam matrix was more compact. However, there was a significant fading (p<0.05) of color by the day 21 of storage. This may be influenced by the sugar degradation resulting from Maillard reaction (Potter and Hotchkiss, 1998). Besides, the chili jam exhibited no detectable yeast, mold and aerobic organisms during 21 days of accelerated shelf life storage. Results on sensory evaluation of the chili jam in an opened-container of the chili jam stored at 4-5 o C for 21 days are presented in Table 7. No significant differences (p > 0.05) were observed for all sensory attributes throughout the storage time. Table 6 Physical and microbiological properties of the chili jam stored at 4-5 o C for 21 days a,b,c,d Storage time ph TSS CE Color values Texture Microbial count (Days) ( O Brix) L* a* b* (N) Total Yeast/ aerobic mold d d a a a 0.57 c ND ND c c c a a 0.66 bc ND ND b b b c b 0.75 ab ND ND a a a b b 0.80 a ND ND Means in the same column with different superscripts are different (p < 0.05) by DMRT. ND = not detected. CE color values : L* = lightness (0 = black, 100 = white) a* = redness / greenness (+ = red, - = green) b* = yellowness / blueness (+ = yellow, - = blue) 191

10 Processing and Quality Evaluation of Chili Jam Table 7 Sensory scores of the chili jam stored at 4-5 o C for 21 days Storage time Sensory scores, ns (Days) Appearance Color Flavor Taste Texture Overall acceptance ns = non-significant. Based on a 9-point hedonic scale test (1 = extremely dislike, 9 = extremely like). Conclusion This study indicated that formulating the chili jam using a combination of red hot chili and red bell pepper at the ratio of 2:3 can be achieved with acceptable sensory attributes. The suitable method for reducing the pungency of red hot chili was the use of 5% sugar solution and soaking time 1 hr. The accelerated shelf life study of the chili jam revealed the microbiological safe for at least 21 days. References AOAC Official Method of Analysis. 15 th ed. Virginia: Association of Official Analytical Chemists. Biad Chili Ltd. Co Chili pepper [online]. Available : information.htm. 2 September Cochran, W.G. and Cox, G.M Experimental Design. 2 nd ed. New York: John Wiley and Sons. Fisher, C. and Scott, T.R Food flavors. Cambridge: The Royal Society of Chemistry. Gajar, A-M. and Badrie, N çprocessing and Quality Evaluation of a Low-Calorie Christophene Jam Sechium edule (Jacq.) Swartz,é J. Food Sci. 67: George Mateljan Foundation Chili [online]. Available : com/chili. 2 September James T. Ehler Bell pepper [online]. Available : html/artbellpepper.html. 2 September Potter, N.N. and Hotchkiss, J.H Food Science. 5 th ed. Maryland: Aspen Publishers, nc., Wikipedia Chili pepper [online]. Available : 14 August

11 Õ π ÿ À À å Anchan Choonhahirun received her Master of Science in Biochemistry from Chulalongkorn University. She is currently the Associate Dean for Administration, the School of Science, The University of the Thai Chamber of Commerce. Her main interest is in the utilization of natural products, especially herbs and spices. 193