Introduction

The major fruits grown in these countries are banana, mango,citrus, pineapple and papaya. Besides these, a large number of minorfruits are also grown in the region such as black berry, tamarindetc. Fruits are oftenly procured unripe so that spoilage duringtransportation & storage can be avoided. In recent times there ismuch concern about artificial ripening of fruits in many parts of theworld [1].

Ripening

Ripening is defined as the final stage of development of a fruitwhich involves series of physiological and biochemical events leading to various changes in colour, flavour, aroma and texture that makethe fruits both attractive and tasty. During ripening, the starch inthe fruit breaks down to sugar. The fruit skin colour changes greento bright red or yellow. These changes attract birds, animals andconsumers. The ripening of a fruit depends on the season [2]. Fruitripening is a highly controlled and programmed developmental event,involving the co-ordination of a multitude of metabolic changes andinvolves the activation and inactivation of various genes leading tobiochemical and physiological changes within the tissue [3-6]. Fruitsmay be classified as climacteric or non-climacteric depending onits respiration rate. Climacteric fruits are characterized by transientincrease in both ethylene synthesis and respiration at an early stage of ripening. The peak of ethylene production rate is proportional to thepeak respiration rate. Fruit softening, colour changes, developmentof taste and flavour and a number of other parameters of ripeningprocess are associated with the climacteric cycle. The climactericfruits are avocado, banana, cherimoya, mango, kiwifruits, apple,apricot, cucurbit, jackfruit, papaya, peach, pear, plum and tomato.Non- climacteric fruit does not show any increase in respirationand ethylene synthesis during ripening. In fact, non-climactericfruits show decline in their respiration rate and ethylene productionthroughout the ripening process. Non-climacteric fruits are citrusfruits, cherry, cucumber, grape, lemon, orange, pepper, pineapple,strawberry, etc [7].

Artificial Ripening

In recent times there is much concern about artificial ripening.Various artificial methods of fruit ripening have been observedmostly to meet consumers’ demand and other economic factors.People consume fruits, ripened with hazardous chemicals likecalcium carbide. These pose great health risks to consumers [8].Fruit sellers artificially ripen green fruits even during the due seasonto meet the high demand and make high profit of seasonal fruits.Transporting and distributing fruits from the farmers’ orchardsto consumers’ baskets can take several days. During this time thenaturally ripened fruits may become over ripen and inedible. Apart of naturally ripened fruits can also be damaged during harshcondition of transportation. It indeed increase great economic lossfor the fruit sellers and therefore, to minimize the loss, fruit sellerssometimes prefer collecting fruits before full maturity and artificiallyripen fruits before selling to the consumers [9].

Chemicals used in Fruits

The use of chemicals in food is an issue of major concern. Fruitsare highly nutritious and form an important food item in the humandiet. On the other hand these are highly perishable due to their shortshelf life. These food commodities are contaminated with toxic andhealth hazardous chemicals like calcium carbide, ethylene whichare being used for ripening fruits and protecting them from rottenand damage. Moreover, formalin and some other chemicals are alsoused for extending the shelf life of fruits which are reported to cause several health problems like such as dizziness, weakness, ulcer, heartdisease, skin disease, lung failure, kidney failure and cancer etc. Thewidespread use of formalin and other chemicals for preservation offruits has become a great concern among the people. The chemicalsused as spray solution make fruits attractive [10].

Calcium carbide

Calcium carbide (available as greyish black powder) iscommercially intended for welding purpose but its use in theartificial ripening of climacteric fruits is rampant in many developingcountries. Calcium carbide, once dissolved in water, producesacetylene which acts as an artificial ripening agent. Fruits ripened withcalcium carbide are soft and have good peel colour development butare poor in flavour. Calcium carbide, popularly known as masala, isused extensively in mangoes, bananas and papayas and sometimes inapples and plums. Being cheap (one kg of this chemical costs Rs. 25-30, which can ripen 20 tonnes of fruit), it is indiscriminately used bythe traders in preference to other recommended practices of inducingripening like dipping fruits in a solution of ethephon, or exposure offruits to ethylene gas [11].

However, treatment of fruits with calcium carbide is extremelyhazardous because the chemical is known to contain traces of arsenicand phosphorous. Acetylene gas produced by calcium carbidemay affect the neurological system by inducing prolonged hypoxiagradually culminating to headache, dizziness, mood disturbances,sleepiness, mental confusion, memory loss, cerebral edema andseizures [11].

As per the rule 44 AA of the Prevention of Food AdulterationRules 1955 “No person shall sell or offer or expose for sale or have inhis premises for the purpose of sale under any description, fruits whichhave been artificially ripened by use of acetylene gas, commonly knownas carbide gas.” In spite of such a restriction, calcium carbide is oftenutilized as a ripening agent in commercial front [12].

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Methodology

The study was divided into 4 phases. Phase I includes procurement& selection of fruits. The unripe fruits i.e. banana were procuredfrom the local market of Dabua colony, Faridabad. Unripe bananawith uniform peel colour and size were selected. Ripe bananas wereexcluded. Natural ripening agents i.e. apple, pear and tomato wereprocured from the local market of Dabua colony, Faridabad. The fruitswere selected on the basis of ethylene production. Unripe fruits werenot included as ripening agents. Also bruised fruits were not used inthe experiment. Calcium carbide was procured by the local chemicalvendor from N.I.T 5 local market, Faridabad. The phase II involvedexperimentation & observation. Six bunches of unripe banana werelabelled as A,B,C,D,E,F containing 5 bananas each were exposed tosimilar environmental conditions. These batches were exposed totwo different storage conditions i.e. plastic container & paper bag.

These were exposed to varying amounts & types of ripening agents.Thus while batch A was allowed to ripen naturally, batch B & C wereexposed to 1gram & 2gram calcium carbide respectively. Batch Dwas exposed to single apple while batch E & F were exposed to singletomato & pear respectively (Table 1). Change in the skin-colour fromgreen to yellow was considered as the stage for the ripening of fruit.Phase III includes, subjective evaluation, which was done to assess theripening ability of different batches. Hedonic scoring methods wereused in the sensory evaluation of bananas. For sensory evaluationprecautions were taken as recommended by FSSAI, the banana waspealed and then sensory evaluation was done. Objective evaluationwas also done by assessing the titrable acidity and performingBenedict’s test. Phase IV includes statistical analysis, SPSS version 20was used to assess mean, standard deviation and ANOVA.

Table 1: Formulation of batches for experiment.

Precaution - Fruits were pealed and washed thoroughly withwater before sensory evaluation.

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Results and Discussion

It was observed that the batches stored in plastic container differin the ripening ability. The banana stored in batch A took 10 daysto ripen while batch B & C took 5 days respectively. Batch D took 4days while E & F took 7 & 9 days respectively. Those batches storedin paper bags took 10 days to ripen. Ripening was similar in all thebatches of paper bag storage (Figure 1).

Figure 1: Duration taken by different ripening agents for ripening of banana.BATCHES: A) Control B) Unripe fruit + 1 gram calcium carbide C) Unripefruit + 2 gram calcium carbide D) Unripe fruit + Apple E) Unripe fruit + PearF) Unripe fruit + Tomato.

Sensory evaluation revealed (Table 2) that bananas stored withapple (batch D) were the most acceptable in plastic container storage.However no significant differences were observed in the differentbatches stored in paper bag storage. Hedonic scoring was done tocollect the data.

Table 2: Mean acceptability score of attributes between the batches: Hedonic scoring (container storage).

Table 5: Benedict’s test for banana - plastic storage.