Fruit Extract of Punica granatum Used as a Natural Indicator in Acidimetry Titration

INTRODUCTION

Punica granatum, also known as Punica malus is a species of the Punica genus, belonging to the family Lythraceae. The pomegranate is mostly native to the Iranian Plateau and India. It has been cultivated in the caucasus, since ancient times. It is widely cultivated throughout iran , afganistan, egypt, pakistan, china,burma ,south arabia,israel. the drier parts of southest asia, indonesia the region of Southern europe, and tropical south.[1] Introduced into latin america and california by spanish settlers in 1769, pomegranate is now cultivated in parts of California and arizona  for juice production[2]

An ancient fruit, pomegranate is mentioned in Europe as early as the Iron-Age, Greek Methology in the Homeric hymns. Yet, it has still to reach mainstream prominence as a consumer fruit in commercial markets of North America and the Western Hemisphere.

The leaves are opposite or sub-opposite, glossy, narrow oblong, entire, 3–7 cm long and 2 cm broad. The flower are bright red, 3 cm in diameter, with four to five petals (often more on cultivated plants). Some fruitless varieties are grown for the flowers alone. The edible fruit is a berry and is between a lemon and agrape fruite in size, 5–12 cm in diameter with a rounded hexagonal shape, and has thick reddish skin and around 600 seeds.[4] Each seed has a surrounding water-laden pulp the aril ranging in color from white to deep red or purple.

Pomegranates are drought-tolerant, and can be grown in dry areas with either a Mediterranean winter rainfall climate or in summer rainfall climates. In wetter areas, they are prone to root decay from fungal diseases. They are tolerant of moderate frost down to about −10c (14f)

Punica granatum nana is a dwarf variety of P. granatum popularly used as bonsai trees and as a patio plant. It could well be a wild form with a distinct origin. The only other species in the genus Punica is the  (Punica protopunica), which is endemic to the island of scotara. It differs in having pink (not red) flowers and smaller, less sweet fruit.

Pomegranate aril juice provides about 16% of an adult's daily vitamin c requirement per 100 ml serving, and is a good source of vitamin B5 (pentothenic acid), pottasium and polyphenols, such as tannis and flavanoids.[5][6]

The most abundant polyphenols in pomegranate juice are the hydrolyzable tannins called ellagitannis formed when ellagic acid binds with a carbohydrate punicalories are unique pomegranate tannins with free-radicle scavenging properties in laboratory experiments[7] and with potential human effects.[8] Punicalagins are absorbed into the human body and may have dietary value as antioxidant, but conclusive proof of efficacy in humans has not yet been shown.[9][10] During intestinal metabolism by bacteria, ellagitannins and punicalagins are converted to urolithins which have unknown biological activity in vivo.[11][12]

MATERIAL AND METHODS

The pomegranate fruit was taken and peeled the epidermis. The arils were collected from fruit and the juice was extracted by separating the seeds manually. The experimental work was carried out by using the same set of glasswares for all type of titrations. As the same aliquots were used for both titrations i.e. titration by using standard indicators and pomegranate extract, the reagent were not calibrated. The equinormal titration was performed using 20 ml of titrate with three drops of indicator and the assay of sodium bicarbonate was carried out.

RESULTS AND DISCUSSION

The pomegranate extract was screened for its use as an acidimetry indicator in acidimetry titrations, and the results of this screening compared with the results obtained by standard indicator methyl orange for strong acid v/s weak base (H2SO4 and NaHCO3).

The parameters are shown in Table 1. In this titration the equivalence point obtained by the pomegranate extract matched with the equivalence point obtained by standard indicator. The results of screening were listed in Table 2. Punica granatum fruit extract alone can serve the purpose of indicator in strong acid and weak base titration. Lastly we can say that it is always beneficial to use Punica granatum fruit extract as an indicator in all types of acidimetry titrations because of its economy, simplicity and availability.

Table 1: Parameters Used For Analysis and the Comparison of Color Change.

Indicator   Color Change

Titrant                         Titrate                         Standard                     Pomegranate Juice

(Methyl orange)

H2SO4 NaHCO3 Light Orange to Pink          Colorless to Pink

H2SO4: Sulphuric Acid, NaHCO3: Sodium Bicarbonate

Table 2: Screening Results For Titration.

Sr.       Titration                      Strength in                  Indicator                                 Readings

No.      (Titrant v/s Titrate)    Normality                                                                   in ml

1          H2SO4 v/s NaHCO3 0.5                          Methyl orange                          22

Pomegranates extract                20

H2SO4: Sulphuric Acid, NaHCO3: Sodium Bicarbonate.

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