EVALUATION OF CHANGES IN BIOCHEMICAL PARAMETERS OF BANANA (MUSA SPP.) STORED IN POLYPROPYLENE PACKAGINGS.

This study was carried out to evaluate the effect of polypropylene packaging on biochemical parameters of plantain. Two varieties of banana ( French 2 and Corne 1) harvested at 70 and 75 days after floral apparition have been stored at 25 °C in 0.235 and 0.303 mm thick polypropylene (PP) packaged. Biochemical characteristics such as pH, titratable acidity, ripening stage, moisture content, ash, reducing sugars and starch content were determined. The results showed that Polypropylene packaging stabilized the biochemical characteristics of plantain. The result about French 2 indicated stability of parameters between the 12 th and 14 th day of storage in the bags of 0.235 mm thickness and 18 th and 20 th day of storage in the bags of 0.303 mm thickness. However, for Corne 1 variety, the parameters were stable between 10 th and 12 th days of storage and 16 th and 18 th days respectively in packages of thickness 0.235 and 0.303mm. Significant differences were not observed for the same treatment at maturity levels of 70 th and 75 th days. The stability time of the physicochemical characteristics of French 2 variety is significantly longer.

This study was carried out to evaluate the effect of polypropylene packaging on biochemical parameters of plantain. Two varieties of banana (French 2 and Corne 1) harvested at 70 and 75 days after floral apparition have been stored at 25 °C in 0.235 and 0.303 mm thick polypropylene (PP) packaged. Biochemical characteristics such as pH, titratable acidity, ripening stage, moisture content, ash, reducing sugars and starch content were determined. The results showed that Polypropylene packaging stabilized the biochemical characteristics of plantain. The result about French 2 indicated stability of parameters between the 12 th and 14 th day of storage in the bags of 0.235 mm thickness and 18 th and 20 th day of storage in the bags of 0.303 mm thickness. However, for Corne 1 variety, the parameters were stable between 10 th and 12 th days of storage and 16 th and 18 th days respectively in packages of thickness 0.235 and 0.303mm. Significant differences were not observed for the same treatment at maturity levels of 70 th and 75 th days. The stability time of the physicochemical characteristics of French 2 variety is significantly longer.  (Grierson et al., 1981, Lizada, 1993. Modified atmosphere packaging (MAP) of fresh banana refers to the technique of sealing actively respiring banana in polymeric film packages to modify the O 2 and CO 2 levels within the package atmosphere. It is often desirable to generate an atmosphere low in O 2 and/or high in CO 2 to influence the metabolism of the product being packaged or the activity of decay-causing organisms to increase storability and/or shelf life (Workneh et al. 2009). In addition to atmosphere modification, MAP vastly improves moisture retention, which can have a greater influence on preserving quality. Further more, packaging isolates the productfrom the external environment and extends the shelf life of the produce (Beaudry, 2000).
Investigations on the use of polypropylene bags for extending the green life of plantain fruits have been carried out (Loa et al., 2017). This study proposes to follow some biochemical parameters of plantain stored with polypropylene packaging.

Material And Methods:
Plant material: In this study two varieties of plantain such Corne 1 and French 2 were used. These plantain varieties harvested at 70 th and 75 th days after floral apparition were obtained from plantations of Yamoussoukro area (6°49' N and 5°16' O), located in the center of Côte d'Ivoire.

Packages:-
The fruits were packed in polypropylene (PP) bags of thickness 0.235 and 0.303 mm due to 10 kg per bag. The extremity of the bags was firmly closed with a thread.
Storage conditions:-Ten (10) kg of unpackaged bananas served as a control. The whole of packaged and unpackaged bananas were stored at ambient conditions at 25 °C during 25 days. Every week, a fruit has been removed and subjected to various physicochemical analyzes. The sampling consisted of three batches of plantain. -Batch 1: control (F70 T, F75 T, C70 T and C75 T) -Batch 2: fruit packed in PP bags of 0,235 mm thickness (F70 SPI, F75 SPI, C70 SPI and C75 SPI) -Batch 3: Fruit packed in PP bags of thickness 0.303 mm (F70 SPII, F75 SPII, C70 SPII and C75 SP II).

Biochemical analyzes:-
The hydrogen potential (pH) of the samples was measured with a pHmeter (METROM E 520). Titratable acidity was determined by direct titration of diluted pulp with 0.1 N NaOH as described by Ranganna (1986). Moisture content was determined by desiccation in a drying oven at 105 °C during 24 hours (AOAC, 2005). Reducing sugars were determined according to the method of Bernfeld (1955) using 3.5-dinitro-salicylic acids. The ripening stages were determined by the methods of Lii et al. (1982). Proteins contents were measured by Kjeldahl method (AOAC, 2005). Ashes were obtained by calcination in a muffle furnace at 550 °C during 6 hours (AOAC, 2005). Starch content was determined by the formula of Bertrand and Thomas (1910). All determinations were performed in triplicates.

Statistical analysis:
The analysis data were processed using STATISTICA 7.0 software. An analysis of variance (ANOVA) with 3 classification criteria (type of cultivar, degree of maturity and type of packaging) was carried out to evaluate the effect of the type of packaging on the biochemical parameters of the two varieties. The Duncan test at the 5% threshold was used to rank the mean.

Results:
Evolution of pH and titratable acidity during storage at 25 ° C : Figure 1 and 2 represents respectively pH and titratable acidity of fruit pulp of French 2 (A) and Corne 1 (B) varieties harvested at 70 th and 75 th days, then stored at 25 °C. pH of controls varied significantly from 6.25 to 4.16 and from 6.39 to 4.14 respectively in French 2 and Corne 1 varieties harvested at 70 th and 75 th days. On the other 324 hand, the pH of both varieties stored with polypropylene bags of thickness 0.235 and 0.303 mm were stable during 16 th and 20 th days of storage respectively. The titratable acidity of the control pulps increased significantly (p <0.05) in the two varieties harvested at 70 th and 75 th days. Figure 2A and 2B showed a stability of titratable acidity during 14 days into fruits packaged in bags of thickness 0.303 mm.      Ripening stage, moisture, ash and protein content:-These parameters were showed into table 1 and table 2. The results of ripening stages show that the control spend 7 days to pass from green stage at more yellow than green stage, while the more advanced stage such as the yellow with extremity green is observed after 18 and 20 days of storage respectively in packaging in PP of thickness 0,235 and 0,303 mm.
The moisture content was found increased till last day of storage. They ranged from 60.07 to 70.08 % and from 61.64 to 71.79 % with a significant increase observed from the 7 th and 25 th day respectively in the control pulps of

Discussion:-
The study of the evolution of the biochemical characteristics of French 2 and Corne 1 varieties showed significant variations between the unpackaged control samples and the fruits packed in the polypropylene bags. In general, there is a significant change in biochemical characteristics in unpackaged fruit from the 7 th day of storage.
The pH of fruit decreases significantly during storage. Similar results have been reported by Assemand et al., (2012). The gradual decline in fruit pH during maturation or storage was attributed to an accumulation of acidic organic materials, such as malic acid, which are generally associated with maturation (Wyman and Palmer, 1964).
The increase in pulp moisture content during ripening may be due to carbohydrate breakdown and osmotic transfer from the peel to pulp due to its high sugar concentration (Izonfuoand Omuaru 1998, John and Marchal1995). The results showed an increase of protein and ash contents during storage. With respect to proteins, it has been attributed to possible enzyme conversion and / or protein synthesis during ripening (Tressel et al., 1975). Similarly, the increase of ash content has been reported by several authors (Nimsung et  . The small variations in physicochemical characteristics observed in fruit packed in polypropylene bags could be explained by the presence of CO 2 in these bags. This gas is known for its inhibitory action on the enzymes of the respiratory chain, and especially for its opposition to the action of ethylene, phytohormone stimulating fruit ripening. Authors such as Chamara and al. (2000) and Dupin (1992) have shown in their studies that CO 2 would inhibit the activity of enzymes in the starch degradation chain. All these physiological actions lead to a slowing of the metabolism, thus prolonging the shelf life and stabilizing the physicochemical characteristics of the fruits during storage (Varoquaux et al., 2002). The shelf-life of PP packages with a thickness of 0.303 mm is significantly (p <0.05) longer than in packages with a thickness of 0.235 mm. Similar results were obtained by Yao et al., (2014). According to these authors, the permeability of the sachets is, in general, inversely proportional to their thickness. The amount of CO 2 accumulated will therefore be higher in polypropylene bags of thickness 0.303 mm than those of 0.235 mm.

Conclusion:-
Modified atmosphere created by the polypropylene bags stabilized biochemical lparameters like pH, titratable acidity, starch ans sugar content, ash, moisture and protein content. These parameters were generaly stable until 14 th to 18 th into Corne 1 and French 2 respectively. However, polypropylene bags 0.303 mm thick produced better results than polypropylene bags with 0.235 mm thick. Significant differences were not observed for the same treatment at maturity levels of 70 th and 75 th days. The stability time of the biochemical characteristics of French 2 variety was significantly longer.