International Journal of Drug Development and Research

Keywords

Browning reaction , Citric acid , Malic acid , Nitrosulfur compound , Organosulfur compound , Rasmol studies

INTRODUCTION

Lack of attention to flavor compounds in pulp manufacturing programs has led to flavor mediocrity in Pulp manufacturing process and its lessened acceptability. Organic acids are key components in the perception of mango flavor as in most fruits [1,2] Predominant acids like Citric Acid(CA) and Malic Acid(MA) were added to see how it impacted various components like pH, Total soluble solids (TSS), acidity, sugar content and contents of the product [3]. This study conducted determines the effects of varying acid concentrations, both Citric and Malic acids in combinations as different treatments. (100%CA0%MA, 66%CA33%MA, 50%CA50%MA, 33%CA66%MA, 0%CA100%MA) on flavor properties of canned pulp to better understand how flavor components impact our sensory perceptions [4,5]. Determining the relationship of chemical measures to sensory data would allow their use in lieu of sensory studies to predict certain flavor properties. Thus, we hope to increase understanding of mango flavor and identify useful tools for pulp manufacturers in improving mango flavor quality.

Also the second and novel part of these studies on the pulp include: Brief bioinformatic analysis using RasMol V2.7.1 Developed by Roger Sayle - which reads in a molecule’s coordinate file and interactively displays the molecule on the screen in a variety of color schemes and molecular representations. It was used for visualization of the structures of pectin, melanin and allinase in our study as it can guide the mango based fruit industry manufactures in better understanding their product from its structural level. Estimation of amount of Melanin formed in the product on its exposure to oxygen, the changes in the browning process going on leads to help the manufacturers to increase the stability of their product and thereby its consumer acceptability [6,7]. Browning of fruit occurs because of a chemical reaction between Catechol and Oxygen. The product of this reaction, Benzoquinone, is a brown compound that is toxic to bacteria. When the fruit peel is injured, Oxygen reacts with the Catechol, defending the fruit. Shelf life of the pulp can therefore be extended by not letting Oxygen come in contact with injured regions. Checking for levels of Allicin an organosulfur compound formed by the action of the enzyme allinase on allin and has been presumed to be a very strong antioxidant whose presence was also tested for in mango pulp as a part of our study [8]. And also for the presence of Glucosinolates which are derivatives of glucose and amino acids and are known to contain nitrogen and sulfur compounds formed as secondary metabolites mostly found in the plant varieties related to Brassiacaceae families [9]. The well known theory for the usefulness of their presence is that upon tissue damage leads to the activation of plant defence mechanism to release compounds like isothiocyanate, nitrile, thiocyanate upon hydrolysis rendering it toxic to herbivores and pathogens .

MATERIALS AND METHODS

Procurement of the materials:

A local ripened mango variety (chaunsa) was selected from the local market of Chittoor. The fruit was thoroughly washed to remove dirt, dust, pesticide residues and microflora on the surface of the fruit. A Can of 3.1 Kg mango pulp was purchased from a local mango pulp processing Industry.

Pulp extraction, treatments preparation and storage:

Mangoes were passed through a mango pulper to separate natural pulp from the stones and skin and canned pulp was also obtained which was mixed with acids as per treatment combination presented in Table 1 and seen in Fig 1 . The treated pulp samples were transferred to sterilized beaker and stored under ambient conditions (30-40ºC) [10] .

Physio-chemical analyses of the pulp:

Total soluble solids (TSS) were determined directly in each sample by using refractometer (Atago 3810- Japan) and expressed as Brix. Sugar was determined by colorimetric method, acidity was determined titrimetrically with the visual acid-base method and the pH was determined with a digital pH meter. The above data were statistically analyzed and the mean of different parameters was compared.

Sensory evaluation of mango pulp samples:

Each sample of mango pulp was presented to a trained panel of judges for sensory evaluation for colour, taste, flavor and overall acceptability using two sensory evaluation methods which include :

Hedonic scale

In accordance with the method described by Larmond et al. [11] The panel members were selected on the basis of their ability to discriminate and scale a broad range of different attributes of mango and mango products.

Paired Comparison test:

Pairs of samples were handed down to the panel members. These samples have specific code for each. Different samples are given in each pair which differs in the intensity of one characteristic, e.g. sweetness, bitterness or rancidity. The samples as a pair are looked for the ones with more or less intensity. The panel members, students of biotechnology department of VIT University analyzed all the pairs according to the training received by them for evaluating different parameters. Each parameter estimated in this test is defined and was well versed to the panel.

Breif Bioinformatic studies:

RasMol V2.7.1 developed by Roger Sayle (Biomolecular Structures Group, Glaxo Welcome Research and Development) Stevenage, Hertfordshire, UK. The structural analysis of Melanin, Pectin and Allinase (Accession no: 1F9B,1IDJ,1LK9 in PDB respectively) was obtained by executing the program in Rasmol.

Estimation of Melanin composition:

Making of master solutions:

Both canned and natural pulp samples were taken into 2 beakers and 30 ml of 1N HCl was added to each. This was followed by the addition of 20ml of 1N NaOH to each of these beakers. These beakers were later stored in waterbath at 72°C for 10 minutes.

Estimation procedure:

1ml of each of the master solutions were taken into 2 test tubes. 5ml of 1N HCl was added to each of these test tubes.This was followed by the addition of 2ml 1N NaOH to each of these 3 test tubes, so that proper pH was maintained .These test tubes were then placed in a water bath at 72 °C for 10 minutes.1ml of 1N HCl was added to these test tubes after they were taken out of the water bath followed by the addition of 1N NaOH to each of them. Again these test tubes were kept in a waterbath at 72 °C for 10 minutes. These solutions were then allowed to cool and were kept in an Ice box.The O.D. was measured at 410nm using a spectrophotometer. Also the same procedure was repeated to see the affect of acids on melanin composition. Therefore different canned pulp treatments were also estimated for their melanin levels.

Allicin Estimation:

Both pulp samples were added to 5g BaCl2 with 5ml of distilled water and kept for incubation and the absorbance was read at 610nm [12,13.14]. Also, different treatments of the canned pulp were estimated for their allicin composition.

Glucosinolate Estimation:

Both pulp samples (canned and natural) were added to 0.5g BaCl2 with 5ml of distilled water and kept for incubation and the absorbance was read at 610nm. Also, different treatments of the canned pulp were estimated for their glucosinolate presence.

RESULTS AND DISCUSSION:

Correlation analysis :

We correlated the values of TSS and pH as seen in Fig 2,3,4. by different statistical analysis methods like Regression plots, Pearson’s correlation coefficient and Spearman’s by a statistical software we found that these two variables are positively correlated to each other and just about change in one variable could impact the other which can be significant inference in the concept of pulp processing [15].

Correlation analysis between pH and TSS:

Experiment design : We use Matched pair T-test between means for study of effect of Citric acid & Malic acid on sensory and physiochemical property of pulp. Null Hypothesis (Ho): No effective difference found between sensory characteristics of canned mango pulp due to the addition of varying concentrations of Citric and Malic acid.

Alternate Hypothesis (H1): Addition of varying concentrations of Citric and Malic acid does effect the sensory characteristics of canned mango pulp. Therefore, our null hypothesis Ho was rejected and we have the alternate hypothesis H1 with p value <0.05 being accepted for this sensory quality estimation based on Larmond’s 9-point hedonic scale sensory evaluation.

Paired-comparision test:

Fig 6. includes the paired comparison survey involving different treatments paired with control at each level showed varying degrees of inclination and similarity of treatments towards the control. T2 had highest similarity with that of control as in lots of characteristics it matched the standards of control and therefore the product can be formulated as such to make it appear more like real pulp to increase its marketability .Where as the treatments involving malic acid in predominant concentrations as in T4 and T5 had many sensory characteristics analyzed by as falling inside the low similarity category.

Rasmol structures:

Testing for presence of Allicin, Melanin and Glucosinolate:

As seen in Fig 10.The percentage composition of various biologically significant compounds were estimated in the natural and canned pulp It was also interesting to note that different treatments when tested for the presence of Allicin, Melanin and Glucosinolate showed differing levels of concentrations in each case shown in Table 4. The lowest levels of allicin was found in T2 about 0.14% where as the highest was noted to be about 4.28% in T3.The T5 treatment showed low concentration of melanin about 3.98% and the highest was about 9.43% in T4.The glucosinolate concentrations also varied according to the treatment administered. Low level of about 3.34% in T3 and about 7.9% concentration was observed in T4.Though the exact reason for these findings may not be known it can yet serve as an important parameter to see the effect of acids on the %concentrations of these compounds estimated to in the pulp which can be summarized and graphically represented as below in Fig 11.

ACKNOWLEDGEMENT

The authors want to express their sincere gratitude to Dr.G.Viswanathan, hon’ble Chancellor, VIT University, Vellore for constant support and encouragement for providing the infrastructure and good laboratory facilities to carry out this research work and DST India for financial assistance and support.

Tables at a glance

Table 1 Table 2 Table 3 Table 4

Figures at a glance

Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

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