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Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean (Khóa luận tốt nghiệp)Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean (Khóa luận tốt nghiệp)Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean (Khóa luận tốt nghiệp)Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean (Khóa luận tốt nghiệp)Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean (Khóa luận tốt nghiệp)Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean (Khóa luận tốt nghiệp)Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean (Khóa luận tốt nghiệp)Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean (Khóa luận tốt nghiệp)
THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY PHAM THI CHUYEN Effect of Acidified Sodium Chlorite Against Microbial Contamination and Maintain The Quality of Mung Bean Sprout BACHELOR THESIS Study Mode : Full-time Major : Post-Harvest Technology Faculty :Biotechnology and Food Technology Batch :2013 – 2017 Thai Nguyen, 12/06/2017 THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY PHAM THI CHUYEN Effect of Acidified Sodium Chlorite Against Microbial Contamination and Maintain The Quality of Mung Bean Sprout BACHELOR THESIS Study Mode : Full-time Major : Post-Harvest Technology Faculty : Biotechnology and Food Technology Batch : 2013 – 2017 Supervisors : Assoc Prof Dr Pongphen Jitareerat Ms Trinh Thi Chung Thai Nguyen, 12/06/2017 Thai Nguyen University of Agriculture and Forestry Major Post-Harvest Technology Student name Pham Thi Chuyen Student ID DTN1353140010 Thesis title Supervisors Effect of Acidified Sodium Chlorite against microbial contamination and maintain the quality of mung bean sprout Assoc Prof Dr Pongphen Jitareerat Ms Trinh Thi Chung Abstract: The use of suitable sanitizers can increase the quality and reduce the risk of foodborne illnesses of mung bean sprout The objective of this research was to study the effects of acidified sodium chlorite (ASC which was prepared from mixture of 0.1g/l sodium chlorite and 5% citric acid, pH 2.3) to control microbial contamination and maintain the quality of mung bean sprout The optimal concentation (0.1, 0.25, 0.5 and 1.0 g/l) and dipping time (1, 5, 10, and 15 min) of ASC solution for controlling browning of sprouts was investigated The result revealed that 0.1 g/l ASC for was the best concentration and dipping time for controlling browning This concentration and dipping time was selected to study its effects on microbial decontamination and maintaining the quality of mung bean sprout in compared with non-treated sprout, water washed sprout, and common sanitizing agent (100 ppm sodium chlorite) treated sprout All samples were then stored at 10°C for days The sprout treated with 0.1 g/l ASC for resulted in a significant reduction of bialtotal bacteria, and coliform in comparing with the other treatments ASC treatment also maintained the quality of sprout by inhibiting the browning as indicated by browning score and the changes of color (high L* value and low a* value) Furthermore the treatment with ASC could delay weight loss but did not show any significant negative effect on texture and total soluble solids content Sensory evaluation showed that ASC treated sprout had higher score of color, odor, and over all acceptance than non-treated sprout Therefore, this result indicated that 0.1 g/l ASC for has the potential to minimize microbial growth i and maintaining quality of mung bean sprouts Key words browning, coliform, food born pathogens, sanitizing agent, sprout Number of pages 43 pages Date of Submission 12/06/2017 ii ACKNOLEDGMENT This thesis was completed by support and assistance of a number of people whom I would like to personally thank First and foremost, I would like to express my gratitude to the both my supervisor, Assoc Prof Dr Pongphen Jitareerat of the School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), Thailand and Master Trinh Thi Chung from the Biotechnology and Food Department of Thai Nguyen University of Agriculture and Forestry (TUAF), Vietnam Whose expertise, understanding, patience and provide valuable advice, support and guidance during the my study A special thanks also to my lab teacher, Dr Kanlaya Sripong, for sharing her knowledge, inspiring ideas and discussions, both academic and non-academic Thanks for helping me all the time when I was doing my internship Thanks you for always being supportive and for taking care of me whenever I needed help I would like to thank every people on Post-harvest Technology Department and special thank to all members Postharvest Pathology Laboratory at King Mongkut’s University of Technology Thonburi for helping me fit in and feel welcome from the moment and for the unlimited patience to explain me every doubts which I had during my intership I would also like to all of my teacher in Faculty of Biotechnology and Food Technology for teaching me how to become a good student, helping me how to get knowledge and how to become a useful person And I wish to express my great gratitude to my friends whose support given throughout the months when I stayed at Thailand Finally, I would like to thanks my family, especially to my parents for their unconditional love, overflowing support and words of encouragement Words a truly not enough to express how thankful I am to you iii TABLE OF CONTENTS PART I INTRODUCTION 1.1 Researcher rationale 1.2 Objectives 1.2.1 To determine the optimal concentration of ASC on browning inhibition of mung bean sprouts 1.2.2 To determine the effect of ASC dipping times on browning inhibition of mung bean sprouts 1.2.3 To study the effect of ASC on the microbial contamination and quality of mung bean sprouts 1.3 Scope of study 1.3.1 To study effect of ASC concentration on browning inhibition of mung bean sprouts 1.3.2 To study effect of dipping time of ASC on browning inhibition of mung bean sprouts 1.3.3 To study the effect of ASC on the microbial contamination and quality of mung bean sprouts PART II MATERIALS AND METHODS 2.1 Materials 2.2 Methods 2.2.1 Experiment 1: To determine the optimal concentration of acidified sodium chlorite (ASC) on browning inhibition on of mung bean sprouts 2.2.2 Experiment 2: To determine the effect of acidified sodium chlorite (ASC) dipping times on browning inhibition of mung bean sprouts 2.2.3 Experiment 3: To study the effect of acidified sodium chlorite (ASC) on the microbial contamination and quality of mung bean sprouts 2.3 Parameters measurement 2.3.1 Browning score 2.3.2 Color (L*, a*) iv 2.3.3 Weight loss 2.3.4 Texture analysis 2.3.5 Total soluble solids 10 2.3.6 Sensory evaluation 10 2.3.7 Microbial count 10 2.4 Statistical analysis 11 PART III RESULTS AND DISCUSSION 12 3.1 To determine the optimal concentration of ASC on browning inhibition of mung bean sprouts 12 3.2 Effect of ASC dipping times on browning inhibition of mung bean sprouts 13 3.3 To study the effect of ASC on the microbial contamination and quality of mung bean sprouts 15 3.3.1 Browning score 15 3.2.2 Color change (L* and a* values) 16 3.2.4 Weight loss 17 3.2.5 Texture (shear force) 18 3.2.5 Total soluble solids (TSS) 19 3.2.6 Sensory evaluation 20 3.2.7 Total aerobe bacteria population 23 3.2.8 Coliform population 24 DISCUSSION 26 PART IV CONCLUSION AND SUGGESTION 30 4.1 Conclusion 30 4.2 Suggestion 30 v LIST OF TABLES AND FIGURES Table Effect of concentration and dipping times of ASC on browning inhibition of mung bean sprouts Table Effect of H2O, SH, ASC dip treatment on weight loss of mung bean sprouts during storage at 10oC for days Table Effect of H2O, SH, ASC dip treatment on texture of mung bean sprouts during storage at 10oC for days Table Effect of H2O, SH, ASC dip treatment on brightness value of mung bean sprouts during storage at 10oC for days Table Effect of H2O, SH, ASC dip treatment on a* value of mung bean sprouts during storage at 10oC for days Table Effect of H2O, SH, ASC dip treatment on browning score of mung bean sprouts during storage at 10oC for days Table Effect of H2O, SH, ASC dip treatment on color acceptance of mung bean sprouts during storage at 10oC for days Table Effect of H2O, SH, ASC dip treatment on smell acceptance of mung bean sprouts during storage at 10oC for days Table Effect of H2O, SH, ASC dip treatment on overall acceptance of mung bean sprouts during storage at 10oC for days Table 10 Effect of H2O, SH, ASC dip treatment on total soluble solids of mung bean sprouts during storage at 10oC for days Table 11 Effect of H2O, SH, ASC dip treatment on total bacteria population of mung bean sprouts during storage at 10oC for days Table 12 Effect of H2O, SH, ASC dip treatment on total coliform population of mung bean sprouts during storage at 10oC for days Figure 3.1 Effect ASC concentration to appearance of sprouts Figure 3.2 Effect ASC concentration on browning inhibition of sprouts Figure 3.3 Effect of ASC dipping times to appearance of sprouts Figure 3.4 Effect ASC dipping times on browning inhibition of sprouts Figure 3.5 Effect of H2O, SH, ASC dip treatment on browning score of sprouts vi Figure 3.6 Effect of H2O, SH, ASC dip treatment on L* value of sprouts Figure 3.7 Effect of H2O, SH, ASC dip treatment on a* value of sprouts Figure 3.8 Effect of H2O, SH, ASC dip treatment on weight loss of sprouts Figure 3.9 Effect of H2O, SH, ASC dip treatment on texture of sprouts Figure 3.10 Effect of H2O, SH, ASC dip treatment on total soluble solids of sprouts Figure 3.11 Effect of H2O, SH, ASC dip treatment on color acceptance of sprouts Figure 3.12 Effect of H2O, SH, ASC dip treatment on smell acceptance of sprouts Figure 3.13 Effect of H2O, SH, ASC dip treatment on overall of sprouts Figure 3.14 Effect of H2O, SH, ASC dip treatment on total aerobe bacteria of sprouts Figure 3.15 Changes in mung bean sprouts total bacterial population Figure 3.16 Effect of H2O, SH, ASC dip treatment on total coliform of sprouts Figure 3.17 Changes in mung bean sprouts total coliform population vii LIST OF ABBREVIATIONS ASC Acidified sodium chlorite SC Sodium chlorite CA Citric acid SH Sodium hypochlorite g/l Gram/liter ml Milliliter PCA Plate Count Agar EMB Eosin Methylene Blue Agar FDA Food and Drug Administration CDC Centers for Disease Control CFU/g Colony forming units per gram CFU/g-1 Colony forming unit o Degree celsius C Minute C.V Coefficient of Variation viii reported that chlorine disinfection had a lower effect on the sensory quality of borage and the panelists gave higher scores General, the sensory score of unwashed sprouts had the lowest score from 1th to 4th during of storage A great number of differences in sensory score between samples may be due to the fact that the chemical treated sprouts reduced of respiration rate and ethylene synthesis result in the development of color, off-odours problems and effect to the overall acceptance of product along with the reduce of a wilted or shriveled appearance (Ahvenainen, R and Hurme, E., 1994) Microbial population of mung bean sprouts was closely correlated to safety and quality deterioration The samples dipped with chemical solution helps to control the population of microorganisms on sprouts In this study, the microbial growth on the surface of mung bean sprouts decreased during storage The result indicated that the lowest of the microbial count in the samples treated with 0.1g/l ASC for may be a direct effect of ASC (Fig 3.14, 3.15) Warf (2001) hypothesized that the mode of action of ASC derives from the uncharged chlorous acid, which is formed by the acidification of chlorite Chlorous acid gradually decomposes to form chlorate ions, chlorine dioxide, and chloride ions These reactive intermediates are highly oxidative with broad–spectrum germicidal activity (FDA, 2007) In addition, chlorine dioxide inhibits protein synthesis immediately upon contact with microorganisms ( Benarde, et al., 1967) by its bactericidal action may involve direct oxidation of protein and lipid molecules Warf (2001) reported that SC alone reduced microbial populations nearly as much as ASC This suggests that SC (and not citric acid or the pH of the treatment) is the major antimicrobial factor Therefore, the bactericidal action of sanitizers cannot depend on lowering pH only (Benjamin and Datta., 1995) However, the low pH environment created by citric acid and the highly oxidative intermediate of ASC which are broad spectrum germicidal agent, a vected antibacterial capacity (Paris et al., 2003) The sprouts treatment with 100 ppm SH (Sodium hypochlorite) also significantly decreased the number of microorganisms A study by Adams et al (1989) suggested that an aqueous hypochlorite solution may not wet the hydrophobic surface of the waxy cuticle of the vegetables and the formation of a biofilm could protect the microorganisms against the lethal effects of the hypochlorite Lund (1983) also showed that the contact with a host tissue may inactivate hypochlorite This conclude may be explained for the samples dipped with 0.1 g/l ASC discovered had lower microbial quantity compared with other treatments during the storage 29 PART IV CONCLUSION AND SUGGESTION 4.1 Conclusion ● Immerssing mung bean sprouts in 0.1 g/l ASC for and stored at 10ºC has efficacy on: + Reduce Total Bacteria and Coliform + Reduce browning + Maintain L* and a* value + Show high acceptance scores in color, odour, and overall + No effect on TSS + No effect on texture + Delay weight loss ● ASC can be used to control microbial and maintain the quality of mung bean sprout ● ASC can be used as an alternative sanitizer 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Control 1.00 1.33 1.66 2.66 2.66 100 ppm SH, 1.33 1.66 2.00 3.00 3.00 0.1 g/l ASC, 0.33 0.66 1.33 2.66 2.66 0.1 g/l ASC, 0.66 1.33 2.00 2.66 3.00 0.1 g/l ASC, 10 1.33 1.66 1.66 2.66 3.00 0.1 g/l ASC, 15 0.66 0.66 1.33 2.33 3.00 F-test ns ns ns ns ns ns C V (%) 59.29 47.24 28.28 19.78 11.54 Means within column with different letters are significantly different, * P ≤ 0.05; ns = not statistically different 37 Table Effect of acidified sodium chlorite (ASC) treatment on weight loss of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Weight loss (%) Treatments Days of storage Control 1.55 2.10 2.25 1.28 2.47 H2O, 1.64 1.27 1.55 0.57 3.21 100 ppm SH, 1.43 1.17 1.57 1.29 2.99 0.1 g/l ASC, 1.04 1.57 1.52 1.36 2.33 F-test ns ns ns ns ns ns C V (%) 35.34 31.17 62.93 45.33 19.92 Means within column with different letters are significantly different, ns = not statistically different Table Effect of acidified sodium chlorite (ASC) treatment on texture of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Shear force (Newton) Treatments Days of storage Control 3.07 3.38b 3.75a 4.15 4.18a 3.87 H2O, 3.37 3.37b 3.30ab 3.73 3.55bc 3.78 100 ppm SH, 3.39 4.35a 3.18b 3.58 3.17c 3.50 0.1 g/l ASC, 3.72 3.79ab 3.25b 3.85 3.89ab 3.77 ns * * ns * ns 22.87 25.67 16.91 16.68 17.73 18.73 F-test C V (%) Means within column with different letters are significantly different, * P ≤ 0.05; ns = not statistically different 38 Table Effect of acidified sodium chlorite (ASC) treatment on brightness (L*) value of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Brightness (L* value) Treatments Days of storage Control 72.78 71.22 71.09 69.30b 70.18 66.25 H2O, 71.74 69.54 71.57 70.33b 70.38 68.86 100 ppm SH, 69.02 67.84 73.39 71.04ab 70.76 72.27 0.1 g/l ASC, 71.91 68.40 71.40 72.98a 71.28 71.63 ns ns ns * ns ns 2.27 3.84 2.70 1.74 1.82 3.68 F-test C V (%) Means within column with different letters are significantly different, * P ≤ 0.05; ns = not statistically different Table Effect of acidified sodium chlorite (ASC) treatment a* value of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls a* value Treatments Days of storage Control -0.7bc -0.72b -0.68 -0.45a -0.65 -0.62 H2O, -0.60b -0.63b -0.64 -0.84b -0.71 -0.70 100 ppm SH, -0.44a -0.39a -0.65 -0.50a -0.61 -0.86 0.1 g ASC, -0.83c -0.85b -0.93 -0.89b -0.96 -0.81 ** * ns * ns ns -13.07 -19.11 -24.39 -26.97 -33.41 -31.78 F-test C V (%) Means within column with different letters are significantly different, * P ≤ 0.05; ** P ≤ 0.01; ns = not statistically different 39 Table Effect of acidified sodium chlorite (ASC) treatment on browning score of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Browning score Treatments Days of storage Control 0.67 0.67 2.00 H2O, 0.33 0.67 2.50 100 ppm SH, 0.67 0.67 2.33 0.1 g/l ASC, 0.33 0.33 2.00 F-test ns ns ns ns C V (%) 115.47 98.97 21.74 Means within column with different letters are significantly different, ns = not statistically different Table Effect of acidified sodium chlorite (ASC) treatment on color acceptance of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Color acceptance (score) Treatments Days in storage Control 9.00 6.27c 5.27b 5.53b 6.00 5.40 H2O, 9.00 7.20b 5.53b 5.73ab 6.87 4.80 100 ppm SH, 9.00 7.87a 6.87a 6.33a 6.33 5.53 0.1 g/l ASC, 9.00 7.93a 6.27a 5.80ab 5.80 4.30 F-test ns ** ** * ns ns C V (%) 10.96 16.61 13.40 22.37 31.41 Means within column with different letters are significantly different, * P ≤ 0.05; ** P ≤ 0.01; ns = not statistically different 40 Table Effect of acidified sodium chlorite (ASC) treatment on odor acceptance of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Smell acceptance (score) Treatments Days in storage Control 9.00 7.20 5.67b 5.40 5.60b H2O, 9.00 7.07 5.73b 5.20 6.33ab 4.80 100 ppm SH, 9.00 7.07 6.00ab 5.67 6.47a 5.80 0.1 g/l, 9.00 7.47 6.47a 5.67 5.67b 5.70 F-test ns ns * ns * ns C V (%) 20.50 14.16 14.76 16.91 20.32 5.30 Means within column with different letters are significantly different, * P ≤ 0.05; ns = not statistically different Table Effect of acidified sodium chlorite (ASC) treatment on overall acceptance of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Overall acceptance (score) Treatments Days in storage Control 9.00 6.13c 5.07b 5.47 5.93 H2O, 9.00 6.93b 5.20b 5.53 6.47 4.40 100 ppm SH, 9.00 7.87a 6.80a 5.93 6.73 5.40 0.1 g/l ASC, 9.00 7.87a 6.53a 5.60 5.87 4.60 F-test ns ** ** ns ns ns C V (%) 12.88 17.47 16.43 20.43 34.15 5.30 Means within column with different letters are significantly different, * P ≤ 0.05; ** P ≤ 0.01; ns = not statistically different 41 Table 10 Effect of acidified sodium chlorite (ASC) treatment on total soluble solids content of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Total soluble solids (o Brix ) Treatments Days in storage Control 7.13a 7.70 7.53 6.90b 7.40 8.20 H2O, 6.97a 7.50 7.30 7.10b 7.97 8.50 100 ppm SH, 6.47b 7.20 7.00 7.40a 7.73 7.93 0.1 g/l ASC, 6.87a 7.17 7.33 6.90b 7.53 8.00 ** ns ns * ns ns 2.34 3.73 4.73 2.23 5.50 3.42 F-test C V (%) Means within column with different letters are significantly different, * P ≤ 0.05; ** P ≤ 0.01; ns = not statistically different Table 11 Effect of acidified sodium chlorite (ASC) treatment on total aerobe bacteria population of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Total bacteria Treatments Days in storage Control 5.17a 4.80ab 4.20a 3.89a H2O, 5.08a 5.25a 4.18a 3.84a 100 ppm SH, 5.06a 4.92ab 3.75ab 3.98a 0.1 g/l ASC, 4.45a 4.39b 3.54b 2.98b ** * * ** 7.15 8.90 10.92 9.32 F-test C V (%) Means within column with different letters are significantly different, * P ≤ 0.05; ** P ≤ 0.01 42 Table 12 Effect of acidified sodium chlorite (ASC) treatment on total coliform population of mung bean sprouts during storage at 10oC for days Tap water and sodium hypochlorite (SH) treated sprouts were used as the controls Total coliform Treatments Days in storage Control 5.48a 4.78 4.47a 4.22a H2O, 5.12b 4.84 4.47a 4.05a 100 ppm SH, 5.21ab 4.35 3.96ab 4.27a 0.1 g/l ASC,, 4.46c 4.54 3.70b 3.42b ** ns * ** 4.79 8.75 10.38 8.34 F-test C V (%) Means within column with different letters are significantly different, * P ≤ 0.05; ** P ≤ 0.01; ns = not statistically different 43 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UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY PHAM THI CHUYEN Effect of Acidified Sodium Chlorite Against Microbial Contamination and Maintain The Quality of Mung Bean Sprout BACHELOR THESIS Study... the effect of ASC on the microbial contamination and quality of mung bean sprouts 1.3 Scope of study 1.3.1 To study effect of ASC concentration on browning inhibition of mung bean sprouts The mung. .. Abstract: The use of suitable sanitizers can increase the quality and reduce the risk of foodborne illnesses of mung bean sprout The objective of this research was to study the effects of acidified sodium