The effect of ripening methods and duration on the ripeness level of kepok banana

Ripening is one of the methods used in speeding up the ripeness of kepok bananas and in ensuring the uniformity ripeness. Ripening bananas can be done by using plant leaves, including gamal leaves, lamtoro leaves and banana leaves. The objective of this study was to obtain the best ripening method of leaves and ripening duration for kepok bananas, which do not reduce the quality of bananas. The research method used was a laboratory experiment with data analysis. In this study, four treatments were used in ripening the bananas, i.e. (1) without using any leaves (control), (2) using banana leaves, (3) using gamal leaves and (4) using lamtoro leaves. Each treatment has 3 replications. The amount leaves used in this study was 20% of the weight of bananas. Parameters observed in the ripening process were (1) weight loss, (2) color, (3) hardness (texture), and (4) total dissolved solids. The best value produced for leaves ripening methods was gamal leaves for 5% weight loss parameter, banana leaves for texture parameter and color parameter with value of L* 41.80, a* -0.81, b*15.74, and lamtoro leaves for TPT value of 26.27 Brix.


Introduction
Appropriate time to consume fruits is when they reach their ripening level, which can be observed through their texture, taste, and colour.For example, the best time to consume bananas is when they have been ripened, since raw bananas are difficult to peel, taste sour, and have hard texture.
As bananas have high nutrient contents which consist of proteins, fat, pectin, phenolic compounds, flavonoid, vitamins, and minerals [1], the demand is quite high.To meet this demand, some farmers/sellers carry out ripening methods to speed up the ripening of bananas.One of the methods is by using plant leaves, such as gamal leaves, lamtoro leaves, dan banana leaves, where leaves and bananas are put in a vacuum container until the bananas are ripe.
Other method for ripening bananas is by using chemical compound namely calcium carbide (Asif, 2012), which is widely used in developing countries [2], including Indonesia.However, the compound is considered not safe for human health [2].In addition, it is found that natural ripening produced better characteristic that chemical ripening method [2].
Therefore, the use of leaves in ripening bananas can become an alternative to the use of chemical compound.In this study, we analyzed the best ripening method of leaves and ripening duration for kepok bananas, which do not reduce the quality of bananas.

Materials
One kepok banana cluster harvested around 90 days of fruit age was obtained from commercial farmers.The used of bananas from the same cluster was to ensure the similarity of the banana samples used in this study.The bananas were cleaned, and the good bunches of bananas were chosen for this research.The ripening process were carried out in polypropylene plastic sacks with a size of 45 × 75 cm.

Research treatments
Ripening methods used in this study were by using banana, gamal, and lamtoro leaves in ripening the kepok bananas.Each leave and one bunch of kepok banana were placed in a plastic shack, which then tied tightly.The weight of one bunch of kepok banana used in this study was around 1.1 kg, and the amount of the leave used in each sack was 20% of the weight of the banana bunch.As a control, one bunch banana was ripened in room temperature without any treatments of a plastic sack wrapping and any leave or other compound used.Each of these four treatments (banana leaves, gamal leaves, lamtoro leaves, and control) has three samples.The banana samples were monitored every two days until they reached their ripe levels 2.3.Research parameters 2.3.1.Weight loss.Bananas were weighed before ripening process and every two days until bananas were ripe.The percentage of weight loss were calculated using formula 1:

Colour.
Colour analysis was carried out to determine the colour change during the ripening process.The value of L, a * , and b * were determined using colorimeter.

Hardness (texture).
Banana texture was examine using penetrometer by penetrate kepok banana with the penetrometer needle for 20 seconds.

Total Dissolved Solids (TDS).
Sample bananas were crushed until produced liquid.The liquid then tested for TDS measurement using refractometer Figure 2. Measuring colour using colorimeter, texture using penetrometer, and TDS using refractometer

Results and discussion
The time needed to ripening bananas was different between ripening methods with leaves and without treatment (the control sample).As the function of leaves ripening methods is to speed up the ripening process, these methods only required 8 days to produce ripe bananas.The tightly tied of plastic sacks trap the ethylene produced by leaves, which accelerates the ripening time.Meanwhile, due to no treatment applied in control samples, the samples required 14 days to reach the ripe level of kepok bananas.

Weight loss
The percentage of weight loss for all treatments in this study increased throughout ripening period.
Compared with the leaves ripening methods from day 2 until day 8, control sample showed a higher weight loss.The weight loss percentage was continuously increase up to 22% in day 14, when the bananas had been ripe properly.In contrary, leaves ripening methods showed a small percentage of weight loss, i.e. 5% for gamal leaves and 6% for banana and lamtoro leaves.The short ripening period needed has contributed to this small percentage.In general, weight loss percentage could be used to indicate the freshness and quality of fruits.The higher the weight loss percentage will result in the lower the fruit quality.After harvesting, water percentage in fruits, including bananas, will reduce due to the ongoing transpiration process.In addition, the ongoing respiration process also contributes to the weight loss [3].

Colour.
Colour is an important factor in determine the quality of bananas, especially since this parameter is visible.The ripe level of bananas can be detected through their colour.The change of green to yellow colour due to the reduction of chlorophyll content indicates that the bananas have been ripe [2].
3.2.1.L * value.L * value indicate the lightness where 0 value indicates black and 100 value indicates white.The result of this study showed a downward trend for all treatments.This is due to the changing colour from green to yellow-brown in the process of ripening bananas.In general, non-treatment bananas (control) generated higher L * value than leaves bananas, while banana leaves had the highest L * value among leaves ripening methods.3.2.2. a * value.a * value represents the greenness and redness of an object, with negative a * value direct to green, and positive a * value direct to red.As green colour in unripe banana will disappear as the ripe level increase, all treatments showed similar trends, from negative a * value to positive a * value.Compared all of the treatments at the end of ripening period, gamal leaves had the highest a * value.

Total Dissolved Solids (TDS)
One of parameter of ripe bananas is their sweetness.Throughout ripening period, the sweetness of bananas will increase, due to the changing of their starch into sugar.Total Dissolved Solids (TDS) can be used to measure the sugar level of bananas.In this study, TDS level of control was the lowest, while lamtoro leaves provided the highest of TDS level at the end of ripening period, although it was not really different with the other 2 leaves.

Figure 8. TDS value of all treatments
The research results showed that ripening bananas using banana leaves produced better colour and texture compared to other leaves.However, gamal leaves provided the lowest weigh lost and lamtoro leaves provided the best sweet taste.

Conclusions
Based on the research results, it can be concluded that: 1. Banana leaves produced the best colour and texture for ripe bananas, while the lowest weigh lost was in the ripening method using gamal leaves.In the case of lamtoro leaves, they provided the best sweet taste of ripe bananas.2. The quality of ripening banana produced from leaves ripening methods were good, based on the colour, texture, and TDS 3. The time needed to reach appropriate ripe level of bananas using leaves ripening treatment was shorter than not using any ripening treatment.

Figure 3 .
Figure 3.The percentage of weight loss of leaves ripening methods (banana, gamal, and lamtoro leaves) and without leaves ripening method (control).

Figure 4 .
Figure 4. L * value in the ripening process of all treatments

Figure 5 .
Figure 5. a * value in the ripening process of all treatments 3.2.3.b * value.The blueness and yellowness of an object was represented with b * value.Negative b * value showed a trend toward blue, while positive b * value showed trend toward yellow.Interestingly, all the treatment showed a downward trend, with control (no treatment) had the highest b * value.The downward trend leaded to negative value, which was toward blue, not toward yellow as expected in ripe bananas.In leave ripening method group, banana leaves had the highest b * value.

Figure 6 .
Figure 6.b * value in the ripening process of all treatments3.3.TextureAll treatments showed a downward trend, since ripe bananas are tenderer than unripe bananas.Interestingly, at the end of ripening period, non-treatment (control) and leave treatment ripening methods showed similar texture value, i.e. around 3N.However, banana leaves showed the highest texture value throughout the ripening period in the leave ripening group.

Figure 7 .
Figure 7. Texture analysis value for all treatments