Postharvest Quality Response of Tomato (Lycopersicon Esculentum, Mill) Fruits to Different Concentrations of Calcium Chloride at Different Dip- Times

AMERICAN JOURNAL OF FOOD AND NUTRITION Print: ISSN 2157-0167, Online: ISSN 2157-1317, doi:10.5251/ajfn.2015.5.1.1.8 2015, ScienceHuβ, http://www.scihub.org/ajfn Postharvest Quality Response of Tomato (Lycopersicon Esculentum, Mill) Fruits to Different Concentrations of Calcium Chloride at Different Dip- Times Eric Arthur, Ibok Oduro and Patrick Kumah Department of Food Science and Technology, Kwame Nkrumah University of Science and Technology, Kumasi-Ghana. Email address: ericarthur.arthur@gmail.com. Telephone number: +233-209140989 iquomma@yahoo.com, Telephone number: +233-244288315 Department of Horticulture, Kwame Nkrumah University of Science and Technology, Kumasi-Ghana Email address: patrickumah@gmail.com, telephone number: +233-208168668 ABSTRACT The postharvest quality of tomato fruit harvested at the pink stage and dipped in 3 different concentrations of CaCl2 for different dip times (30, 20 and 10 minutes) were studied. Tomato fruits dipped in 6% CaCl2 for 30 and 20 minutes retained significantly (P < 0.05) higher level of firmness, titrable acidity and vitamin C than fruits dipped in 2% CaCl2 and the control. The calcium chloride treated fruits showed significant (P < 0.05) levels of delay in the changes of weight loss, firmness, titrable acidity, total soluble solids, vitamin C and decay than fruits without CaCl2 treatment. Tomato fruits dipped in 6% CaCl2 for 20 or 30 minutes maintained significantly (P < 0.05) higher vitamin C and firmness than fruits dipped for 10 minutes and the control. Therefore, postharvest quality of tomato fruits such as vitamin C, titrable acidity, weight and firmness can be maintained by harvesting at the pink stage and dipping in 6% CaCl2 for 20 minutes. Maintaining these postharvest parameters may help enhance the profitability of farmers and marketers of tomato fruits and as well improve the livelihood and food security of Ghanaian communities. Key word: Quality, dip time, storage life and postharvest INTRODUCTION Tomato (Lycopersicon esculentum Mill) is considered as one of the most important vegetables in the world and is known to belong to the Solanaceae family (Peralta and Spooner, 2007). The crop has been reported to be widely cultivated in Africa and the world at large (Norman, 1992; FAO, 2001). Tomatoes consumption in the world is very high compared to other vegetables, in Ghana for instance, the fruit is regarded as an obligatory ingredient in the daily meal of the majority of the people (Ellis et al., 1998). The tomato fruit can be consumed fresh or cooked and may also be processed into purees, juices and ketchup. Tomato fruit is also considered as one of the important sources of vitamin C, carotenoids and other minerals such as iron and phosphorous that are necessary for healthy growth. Tomato fruits do not only constitute a great source of lycopene but also contain carotenoids with a high oxygen-radical scavenging and quenching capacity (Dumas et al., 2003; Babalola et al., 2010). Despite these numerous benefits of tomatoes, various factor such as physical injuries, high storage temperature, moisture content and ethylene production have been cited to limit its storage life (Mutari and Debbie, 2011). Power is one of the popular cultivars of tomatoes in Ghana and has been reported to be very perishable (Nyamah, 2011). Therefore, several postharvest interventions have been introduced to help maintain quality and extend storage life. These interventions in include low temperature storage, wax coating, modified atmosphere package and others. The combinations of treatments such as low temperature, waxing, low oxygen and high carbon dioxide storage and ethylene inhibitor such as CaCl2 treatment have been reported to have the potential to 1

extend the storage life of fresh produce such as tomatoes (Genanew, 2013). A study by Senevirathna and Daundasekera (2010) indicated that, fruits treated with CaCl2 exhibited firmer texture. The firmer texture of CaCl2 treated fruit may be due to the inhibited action of polygalacturonase, which is an enzyme that facilitates the degradation of pectate during ripening. According to Bhattara and Gautam (2006), calcium in the cell wall serves as a binding agent in the form of calcium pectate. This helps to maintain the quality and extend the storage life particularly by delaying ripening and senescence as well as reducing respiration rate and physiological disorder. However, there had been disparities in the recommended concentrations of calcium chloride (CaCl2) appropriate for maintaining quality and prolonging storage life of the fruit. Some researchers recommended lower concentration such as 1.5% CaCl2 (Nirupama et al., 2010), while others recommended higher concentration such as 6% CaCl2 (Senevirathna and Daundasekera, 2010). Besides, very little information exists on the appropriate dipping time for the fruit at a given concentration. There is the need to investigate further, the effect of calcium chloride concentration at a given dip time. The perishable nature of this cultivar (Power) and its associated consequences necessitate an exploration into appropriate concentration of postharvest calcium chloride treatment and the dip time to maintain the quality the tomato fruits. Therefore, the general objective of this study was to determine the effect of dipping tomato fruits (cv. Power) in different concentrations of CaCl2 for different dip-times on the postharvest quality of the fruits. MATERIALS AND METHODS Tomato fruits (Power cultivar) were harvested at the pink stage of maturity based on the colour of the pericarp (USDA, 2010). Fruits were harvested with the calyx attached from a tomato field at Kumawu in the Ashanti Region of Ghana. The harvesting was done 7 weeks after transplanting. Only tomato fruits harvested at the pink stage were packed into wooden boxes with ventilation holes. The tomatoes were then transported within 3 hours to the laboratory of the Department of Horticulture-KNUST, Kumasi, Ghana. Upon arrival in the laboratory, sorting and grading were done to ensure that only wholesome fruits were selected for the study. The fruits were dipped in different concentrations of calcium chloride (2%, 6%, and 0%) at different dip times (10, 20 and 30 minutes). The study was carried out during the period of August- September, 2013 after a preliminary experiment in June, 2013 with average temperature and relative o humidity of 29±2 o C and 82±3%. Parameters Measured: Weight Loss: Fruits were weighed daily and the differences in weight loss were expressed as a cumulated percentage of weight loss from the initial weight of the fruit (Nirupama et al., 2010). Decay: The decay was determined by visual observation for symptoms of fungal mycelia growth. Decay was expressed as accumulated percentage of the total fruit decay divided by the initial fruit number stored (Nirupama et al., 2010). Firmness: Firmness is determined by measuring the force required for making a pre-determine pierce using a standard probe. The registered force at the penetration of a standard probe up to a certain depth is read as the firmness. The firmness of the fruits was measured by the use of penetrometer (FT 327, Effegi, Italy) and the value was expressed in Newtons (Kumah et al., 2011). Vitamin C: This was determined by using the 2, 6- Dichloroindophenol Titrimetric method and the results reported as mg/100g of tomato fruit (AOAC, 2006). Titrable Acidity (TA): 10ml of juice from the various samples were titrated with 0.1M NaOH and the result are expressed in percentage citric acid (Mohammadi- Aylar et al., 2010). Total soluble solids (TSS): The TSS was determined by the use of digital refractometer (Reed MT-032 Brix Refractometer, Taiwan) and the value reported as Degree Brix (Nirupama et al., 2010). Experimental design and statistical analysis: A Complete Randomized Design (CRD) with 3 replicate was used. The data generated were subjected to analysis of variance (ANOVA) using GenStat statistical software version 12. Significant differences were assessed at 5% (p 0.05) level of significance and the mean was separated using least significant different (LSD) procedure. Correlation analysis was carried out to determine the association between the quality parameters using GenStat statistical software version 12. RESULTS AND DISCUSSION Weight Loss: There was a general increase in weight loss in all the treatments from day 1 to day 12. The 2

calcium treated fruits recorded significantly (P < 0.05) lower weight compared to the control as shown in Tables 1. The significantly lower weight loss recorded by the CaCl2 treated fruits could be attributed to the network formation of calcium with the pectin in the fruit cell wall to restrict moisture loss (Genanew, 2013) considering the same dip time, fruits dipped in 6% CaCl2 recorded significantly lower weight loss than fruits dipped in 2% CaCl2 and the control. Significant differences (P < 0.05) in weight loss were also observed among the 3 dip times (30, 20 and 10 minutes) at day 3, 6, 9 and 12. The fruits dipped for 10 minutes recorded a significantly higher (P < 0.05) weight loss than fruits treated for 30 and 20 minutes (Table 1). However, the differences in weight loss between fruits dipped for 30 and 20 minutes were not significant (P > 0.05). Dipping for 20 and 30 minutes might have retarded respiration and transpiration rate which are known to be the major cause of weight loss (Ullah, 2009). Fresh produce begin to wilt when it loses 5-10% of its fresh weight, therefore proper measures must be put in place to control weight loss. Besides, the marketability of fresh tomatoes can be improved by calcium treatment to minimize weight loss, excessive shrinkage, spoilage and metabolic stress after harvest (Zhiguo et al., 2011). Table 1: Effect of postharvest CaCl2 concentration and dip time on the weight loss of tomato fruits stored for 12 days at Temperature and Relative Humidity of 29±2 o C and 82±3% Day 1 Day 3 Day 6 Day 9 Day 12 2%CaCl2-10mins 2.03±0.44 b 4.00±0.40 b 6.12±0.32 a 8.86±0.64 b 11.30±0.44 a 2%CaCl2-20mins 1.90±0.44 c 3.87±0.32 b 5.70±0.74 b 8.37±0.64 c 10.58±0.32 b 2%CaCl2-30mins 1.85±0.64 c 3.86±0.32 b 5.75±0.74 b 8.40±0.44 c 10.58±0.32 b 6%CaCl2-10mins 1.86±0.60 c 3.93±0.41 b 5.51±0.70 cd 9.00±0.74 b 10.70±0.64 b 6%CaCl2-20mins 1.70±0.32 d 3.31±0.67 c 5.13±0.70 d 7.97±0.64 d 9.72±0.61 c 6%CaCl2-30mins 1.75±0.32 cd 3.33±0.67 c 5.16±1.20 d 7.90±0.44 d 9.61±0.91 c Control 2.20±0.44 a 4.43±0.40 a 6.33±1.20 a 9.57±0.44 a 11.97±0.44 a LSD (5%) 0.116 0.196 0.264 0.308 0.393 Firmness: There was a general decrease in firmness in all treatment; however, fruits treated with 6% CaCl2 recorded significantly (P < 0.05) higher firmness than fruits dipped in 2% CaCl2 and the control as indicated in Table 2. The lower firmness in the control may be attributed to the rapid metabolic processes in the control compared to the treated samples. There were also significant differences (P < 0.05) in fruit firmness among the dip times (30, 20 and 10 minutes) of CaCl2. There was a general decrease in firmness in all fruits irrespective of their dip times. Tomato fruits dipped for 30 and 20 minutes recorded significantly (P < 0.05) higher fruit firmness than the fruit dipped for 10 minutes after 12 days of storage. Given the same dip time, tomato fruits dipped in 6% CaCl2 retained significantly higher firmness than the fruits dipped in 2% CaCl2 and the control. Moreover, both fruits treated with 6% and 2% CaCl2 recorded significantly (P < 0.05) higher fruit firmness than the control (0%) as shown in Table 2. The higher firmness recorded by tomato fruit dipped in 6% CaCl2 for 30 and 20 minutes may be attributed to the interaction between the calcium and the pectin in the cell wall of the tomato fruit. Anthon et al. (2005) have reported that the interaction of calcium with pectin is known to be the mechanism for the calcium firming role. The significant interaction recorded between the concentration of CaCl2 and the dip time suggests that, for effective firming role, one needs to apply the right concentration over the right time period. The general decrease in firmness in all the treatments during storage, as indicated in Table 2, may be attributed to the faster weakening of their cell walls. A research conducted by Bhattara and Gautam (2006) indicated that, there is a weakening of middle lamellae during ripening and that may explain the softening of fruit during the ripening process. Calcium, as an essential constituent of the middle lamellae, helps to bind the polygalacturonic acid to each other and, therefore, making the membrane strong and rigid. Firmness is an important indicator of storage potential and, therefore, firmer fruits are known to be more resistant to physical damage during handling and transportation leading to the extension of storage life which has economic benefit. As a result of this, most Postharvest strategies are focused on delaying extensive fruit softening (Ortiz 3

et al., 2011). Maintaining higher firmness of tomato fruit will go a long way to control decay, hence increasing the storage life of the fruit. Table 2: Effect of postharvest CaCl2 concentration and dip time on the firmness (N) of tomato fruits stored for 12 days at temperature and relative humidity of 29±2 o C and 82±3% Day 0 Day 3 Day 6 Day 9 Day 12 2%CaCl2-10mins 4.61±0.10 a 4.05±0.15 c 3.27±0.16 c 2.86±0.15 bc 2.50±0.15 c 2%CaCl2-20mins 4.62±0.12 a 4.26±1.15 b 3.55±0.16 b 3.10±0.15 b 2.90±0.20 b 2%CaCl2-30mins 4.57±0.16 a 4.21±0.15 b 3.40±1.10 bc 3.05±1.20 b 2.86±0.16 b 6%CaCl2-10mins 4.56±1.15 a 4.06±0.06 c 3.27±1.11 c 2.96±0.11 b 2.75±0.16 bc 6%CaCl2-20mins 4.70±0.12 a 4.30±0.10 ab 4.20±0.16 a 3.53±0.15 a 3.30±0.10 a 6%CaCl2-30mins 4.60±0.13 a 4.37±0.12 a 4.06±0.12 a 3.45±1.50 a 3.23±0.10 a Control 4.67±0.10 a 4.00±0.10 c 3.12±0.12 d 2.70±1.20 c 2.10±0.16 d LSD (5%) 0.162 0.124 0.134 0.169 0.145 Decay: The analysis of variance for fruit decay There was, however, no significant difference (p > indicated significant differences (P < 0.05) among the 0.05) in decay levels (%) at day 9 and 12 between levels of the concentrations; fruits dipped in 6% CaCl2 fruits dipped for 30 minutes and 20 minute. The recorded significantly lower levels of decay than the significantly (P < 0.05) lower decay recorded by 2% CaCl2 and the control, as indicated in Table 3. The tomato fruits dipped for 30 and 20 minutes as analysis of variance for fruit decay also showed compared to fruits dipped for 10 minutes (Table 3). significant differences (P < 0.05) among the dip times. Table 3: Effect of postharvest CaCl2 concentrations and dip time on the Decay of tomato fruits stored for 12 days at average Temperature and Relative Humidity of 29±2 o C and 82±3% Day 9 Day 12 2%CaCl2-10mins 18.67±2.20 b 29.33±0.20 b 2%CaCl2-20mins 10.00±4.10 c 22.00±2.30 c 2%CaCl2-30mins 9.33±2.10 c 22.00±2.20 c 6%CaCl2-10mins 15.33±2.00 b 27.33±5.10 b 6%CaCl2-20mins 2.10±2.10 d 14.67±2.30 d 6%CaCl2-30mins 2.00±0.20 d 14.67±2.10 d Control 26.00±2.10a 48.00±2.10 a LSD (5%) 4.77 5.68 Given the same concentration of CaCl2, Tomato fruits dipped for 30 and 20 minutes recorded significantly lower level of decay than fruits dipped for 10 minutes and the control as shown in Table 3. This may be attributed to the fact that, fruit dipped for 20 and 30 minutes had sufficient time for the calcium to penetrate into the fruit to retard physiological processes which also delayed the incidence of decay. Nirupama et al. (2010) reported that, calcium application helps maintain membrane integrity, tissue firmness, cell turgor as well as delaying membrane lipid catabolism and extending storage life of fruit. Nirupama et al. (2010) reported that, calcium application helps maintain membrane integrity, tissue firmness, cell turgor as well as delaying membrane lipid catabolism and extending storage life of fruit. A research conducted by Bhattara and Gautam (2006) indicated that, there is a weakening of middle lamellae during ripening and that may explain the softening of 4

fruit during the ripening process. Firmer fruits are known to be more resistant to physical damage during handling and transportation and thus contribute to extending storage life which has economic benefit (Bhattara and Gautam, 2006). The significant interaction recorded between the concentration of CaCl2 and the dip time suggests that, for effective control of decay, there is the need to dip tomato fruits in the right concentration of CaCl2 over the right time period. Total Soluble Solids (TSS): There were no significant difference in TSS in all the treatments at day 0 and day 12. However, at day 3, 6 and 12, fruits dipped in CaCl2 for 20 or 30 minutes recorded significantly lower TSS as indicated in Table 4. The analysis of variance for TSS showed significant differences (P < 0.05) in fruit dip time in CaCl2. Throughout the storage period, there was no significant difference (P > 0.05) in TSS between fruits dipped for 30 minutes and fruits dipped for 20 minutes. However, the control and the fruits dipped for 10 minutes recorded a significantly higher TSS at day 3 and 9, as shown in Table 4. The conversion of starch to sugar during ripening is the major reason for the continuous rise in TSS during ripening. Besides, organic acids can also be oxidized into sugar to increase the TSS. Table 4: Effect of postharvest CaCl2 concentrations and dip time on the TSS of tomato fruits stored for 12 days at average Temperature and Relative Humidity of 29±2 o C and 82±3% Day 0 Day 3 Day 6 Day 9 Day 12 2%CaCl2-10mins 3.26±0.11 a 3.76±0.12 b 4.16±0.05 a 4.33±0.11 a 4.40±0.10 a 2%CaCl2-20mins 3.30±0.11 a 3.66±0.11 bc 4.06±0.05 ab 4.20±0.16 b 4.33±0.03 a 2%CaCl2-30mins 3.20±0.10 a 3.70±0.10 b 4.03±0.09 b 4.27±0.16 b 4.56±0.03 a 6%CaCl2-10mins 3.30±0.11 a 3.70±0.10 b 4.16±0.05 a 4.33±0.10 a 4.50±0.07 a 6%CaCl2-20mins 3.33±0.24 a 3.56±0.20 c 3.93±0.06 b 4.23±0.10 b 4.50±0.07 a 6%CaCl2-30mins 3.26±0.11 a 3.50±0.20 c 3.90±0.09 b 4.20±0.05 b 4.53±0.04 a Control 3.30±0.10 a 4.00±0.10 a 4.23±0.03 a 4.47±0.06 a 4.56±0.03 a LSD (5%) 0.21 0.167 0.121 0.108 0.175 According to Helyes et al. (2006), malic and citric acid were the main organic acids in the tomato fruit and the range was between 0.3-0.6%. The interaction of the TSS and the acids are important component of sweetness, sourness and flavour intensity in tomato. Carbohydrates constitute about 65% of the soluble solid of ripe tomato fruit. Beside high carbohydrate content and acids are required for best flavour. Hurr et al. (2005) also mentioned that, the development of taste, aroma and flavour of the fruit is attributed to the accumulation of sugars and organic acids in the vacuoles and the production of complex volatiles. Titrable Acidity: There was a general decrease in titrable acidity in all the treatment during storage, CaCl2 treated fruits retained higher titrable acidity than the control. However, there was no significant difference (P > 0.05) in titrable acidity (%) between fruits dipped for 30 minutes and fruits dipped for 20 minutes as indicated in Table 5. Besides, both fruits dipped for 30 and 20 minutes recorded a significantly higher (P< 0.05) titrable acidity than the fruits dipped for 10 minutes during storage, this may be attributed to sufficient dip time which enabled the CaCl2 to effectively retard metabolic processes which accounted for change in titrable acidity and other nutrients. CaCl2 is reported to be an ethylene inhibitor (Genanew, 2013) and ethylene plays an active role in the tomatoes ripening process (Opiyo et al., 2005), and ripening is also associated with the conversion of starch and acids to sugar. The higher amount of titrable acidity recorded in the fruits dipped in 6% CaCl2 for 20 minutes could be attributed the role CaCl2 as an ethylene inhibitor. 5

Table 5: Effect of postharvest CaCl2 concentration and dip time on the titrable acidity of tomato fruits stored for 12 days at average Tempereture and Relative Humidity of 29±2 o C and 82±3% Day 0 Day 3 Day 6 Day 9 Day 12 2%CaCl2-10mins 1.32±0.021 a 1.04±0.21 ab 0.83±0.02 ab 0.69±0.16 ab 0.55±0.03 c 2%CaCl2-20mins 1.28±0.015 a 1.12±0.15 ab 0.91±0.03 a 0.72±0.16 a 0.65±0.03 b 2%CaCl2-30mins 1.35±0.015 a 1.13±0.15 a 0.93±0.02 a 0.74±0.02 a 0.64±0.16 b 6%CaCl2-10mins 1.36±0.021 a 1.00±0.02 b 0.78±0.15 b 0.64±0.04 b 0.54±0.03 c 6%CaCl2-20mins 1.33±0.015 a 1.13±0.03 a 0.97±0.02 a 0.79±0.04 a 0.68±0.16 a 6%CaCl2-30mins 1.33±0.015 a 1.23±0.04 a 0.96±0.21 a 0.76±0.15 a 0.67±0.16 a Control 1.36±0.010 a 1.00±0.09 b 0.74±0.02 b 0.58±0.16 c 0.47±0.03 d LSD (5%) 0.118 0.134 0.074 0.081 0.015 Vitamin C: Similar to the trend in the titrable acidity, all the treatments in this study recorded continuous decrease in vitamin C during storage, as shown in Table 6. From the study, fruits dipped for 20 minutes recorded higher level of vitamin C than fruits dipped for 10 minutes and the control. Considering the same dip time, fruits dipped in 6% CaCl2 recorded significantly higher vitamin C than fruits dipped in 2% CaCl2 during storage as shown in Table 6. There was no significant difference (P > 0.05) in vitamin C content between fruits dipped for 30 minutes and 20 minutes. Besides, both fruits dipped for 20 and 30 minutes recorded a significantly higher (P < 0.05) vitamin C content than the fruits dipped for 10 minutes (Table 6). Table 6: Effect of postharvest CaCl2 concentrations and dip time on the vitamin C of tomato fruits stored for 12 days at average Temperature and Relative Humidity of 29±2 o C and 82±3% Day 0 Day 3 Day 6 Day 9 Day 12 2%CaCl2-10mins 22.67±0.23 a 20.21±0.03 ab 17.37±0.20 c 15.23±0.13c 14.47±0.36 c 2%CaCl2-20mins 22.50±0.23 a 20.83±0.03 a 17.71±0.10 b 16.20±0.06 b 15.28±0.36 b 2%CaCl2-30mins 22.33±0.04 a 21.23±0.20 a 17.85±0.21 b 16.26±0.06 b 15.29±0.20 b 6%CaCl2-10mins 22.60±0.23 a 20.10±0.03 ab 17.36±0.10 c 16.16±0.15 b 15.35±0.10 b 6%CaCl2-20mins 21.93±0.17 a 20.67±0.04 a 18.85±0.03 a 17.47±0.16 a 16.53±0.10 a 6%CaCl2-30mins 21.67±0.34 a 20.27±0.20 a 18.54±0.03 a 17.43±0.16 a 16.46±0.10 a Control 22.67±0.34 a 19.50±0.18 b 16.16±0.23 d 14.56±0.03 d 12.96±0.20 d LSD (5%) 1.71 1.00 0.32 0.58 0.345 Dumas et al. (2003) reported that, tomato fruit is a great source of vitamin C and the mean value of vitamin C recorded ranges from 15 to 23mg/100g raw edible part of the tomato. However, the range may be from 8.4 to 59mg/100g. From the study, the vitamin C content of all the treatments showed a general decrease from day 0 to day 12. Ullah (2009) reported that, respiration and transpiration are the two main main physiological processes that lead depletion of nutrients and deterioration. Besides, harvested fruits still continue their life processes meanwhile there is no longer the transfer of food material and water from the mother plant to the fruit, therefore, it has to depend on its stored food reserves for survival. Eventually, the reserves are depleted, including vitamin C, thus the produce undergo an aging processing resulting in physiological processes that lead depletion of breakdown due to natural decay. Moneruzzaman et al. nutrients and deterioration. The decrease in vitamin C content of tomato fruit during storage may be attributed to the biochemical processes that the fruit undergo before and after harvest. Ullah (2009) reported that, respiration and transpiration are the two (2008) reported that, as the tomato fruit ripens, the ascorbic acid content decreases, therefore, measures to control rapid ripening of tomato fruit has a great influence on the nutrient retention as well as extension of storage life of the fruit. Correlations of quality traits: 6

There was a significantly positive correlation among fruit decay, weight loss and TSS. Such that, fruit decay increased with increasing weight loss and total soluble solid. From Table 7, higher weight loss implied higher TSS and fruit decay. Fruit decay also showed a significantly high and negative correlation with fruit Titrable acidity (-0.65) and vitamin C (-0.79). Thus, an increase in fruit decay led to a decrease in titrable acidity and vitamin C content. The results from the correlation analysis are of great importance to the farmer and the fresh tomatoes traders in assessing the relationship between the postharvest qualities of tomato fruits during storage. For example, a farmer who may not be able to measure the vitamin C content may deduce that, as the decay set in during storage, the vitamin C content also falls. Table 7: Correlation values and P values between postharvest quality traits of tomato fruits stored at 29±2 o C and 82±3% FD WL FF TSS TA VC - Fruit Decay (FD) Weight Loss (WL) 0.55** - Fruit Firmness (FF) -0.84** -0.63** - Total Soluble Solids (TSS) 0.45* 0.31NS -0.49** - Titrable Acidity (TA) -0.65** 0.71** 0.71** -0.45* - Vitamin C (VC) -0.79** -0.39* 0.86** -0.51** 0.47* *=P < 0.05, **=P<0.01 NS = not significant CONCLUSION local government area of Ogun State. Acta SATECH. 3 (2): 14-18 The CaCl2 treated fruits recorded higher firmness, vitamin C and titrable acidity after 12 days of storage as compared to the control. The 20 and 30 minutes dip times were more effective than the 10 minutes in reducing weight loss and decay as well as maintaining firmness, vitamin C and titrable acidity. Tomato fruits harvested at the pink stage and dipped in 6% CaCl2 for 20 minutes facilitated in maintaining firmness, vitamin C and Titrable acidity and, as well, retarded weight loss and decay. Therefore, dipping tomato fruits in 6% CaCl2 for 20 minutes can serve as an important postharvest tool to maintain quality and extend storage life of highly perishable cultivars of tomatoes such as Power, which could lead to higher profitability and improved livelihood for farmers and traders of tomato fruits. REFERENCES 1. Anthon, G. E., Blot, L. and Barrett, D. M. (2005). Improved Firmness in calcified diced tomatoes by temperature activation of pectin Methylesterase. Journal of Food Science. 70 (5): 342-347 2. AOAC (2006). Official Methods of Analysis, Ascorbic Acid in Vitamin Preparation and Juices. 2, 6- Dichloroindophenol Titrimetric Method. Vitamins and Other Nutrients Chapter 45, p. 19. 3. Babalola D. A., Makinde Y. O., Omonona B.T and Oyekanmi M. O. (2010) Determinant of Postharvest losses in tomato production: a case study of Imeko-Afon 4. Bhattarai, D. R. and Gautam, D. M. (2006). Effect of harvesting Method and calcium on postharvest physiology of tomato. Nepal Agricultural Resource Journal. 7: 23-26 5. Dumas, Y., Dadomo, M., Lucca, G. D. and Grolier, P. (2003). Effect of environmental factors and agricultural technologies on antioxidant content of tomatoes. Journal of the Science of Food and Agriculture. 83: 369-383. 6. Ellis, W.O., Olympio, N.S., Mensah, E. P., Adu- Amankwa, A. and Tetteh,Y. (1998). Postharvest problems of tomato production in Ghana - Field studies of some selected major growing areas in Ghana. Journal of the Ghana science association. 1 (1): 55-59. 7. FAO, (2001). FAO Bulletin of Statistics. Food and Agriculture Organization of the United Nations (FAO), 2: 85. 8. Genanew, T. (2013). Effect of postharvest treatment on storage behavior and quality of tomato of fruit. World Journal of Agricultural Science 9(1) : 29-37 9. Helyes, L., Dimeny, J., Pek, Z. and Lugasi, A. (2006). Effect of maturity stage on content, color and quality of tomato (Lycopersicon esculentum L. Karsten) fruit. International Journal of Horticultural Science 12 (1): 41-44. 10. Hurr, B. M., Huber, D. J. and Lee, J. H. (2005). Differential Responses in colour changes and softening of Florida 47 Tomato fruit treated at green and 7

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