E CONTENT ON METALS AND NON-METALS

Isolation  of  Lycopene from Watermelon, Tomato and Papaya

Sangeetha.M.T

B.Ed student, St.Thomas college of teacher education.Pala

Abstract Lycopene is one of the carotenoid naturally occurring in red fruits and vegetables, especially watermelon, tomato and papaya. It is an antioxidant and responsible for red colour of various fruits and vegetables. This studies to analyses the lycopene content from various fruits by a very simple process of lycopene isolation. Identification of lycopene and its chemical structure was done by chemical test. Quantity of isolated pure lycopene was recorded from papaya tomato and watermelon ranged from 1.14mg -3.18mg per 100 gm.  Keywords: Lycopene, antioxidant, papaya, watermelon, tomato.

Introduction

Fruits  and vegetables are main source of natural antioxidant components. Antioxidants give protection against harmful free radicals and reduce rate of cancer and heart disease. The most efficient carotenoid antioxidant is lycopene. Lycopene is a natural pigment  which protects the body by neutralizing the negative effects of oxidants.

Lycopene a carotenoid in the same family as carotenoid, is what gives tomatoes, pink grape fruit, apricots, red oranges, water melons, papaya and guava their red color. Lycopene is not merely a pigment. It is a powerful antioxidant that has been shown to neutralize free radicals, especially those derived from oxygen there by conferring protection against several types of cancer.

Lycopene is a photochemical, synthesized plants and microorganisms but not by animals. It is an acyclic isomer of beta-carotene. This highly unsaturated hydrocarbon contains 11 conjugated double bonds, making it longer than any other carotenoid. As a polyene, it undergoes cis-trans isomerization induced by light, thermal energy, and chemical reactions. Lycopene obtained from plants tend to exit in an all-trans configuration, the most thermodynamically stable form. Humans cannot produce Lycopene and must ingest fruits, absorb the Lycopene and process it for use in the body. In human plasma, Lycopene is present as an isomeric mixture, with 50% as cis-isomers.

Lycopene is a symmetrical tetraterpene assembled from 8 isoprene units. It is a member of the carotenoid family of compounds, and because it consists entirely of carbon and hydrogen, is also a carotene. In its natural, all-trans form, the molecule is long and straight, constrained by its system of eleven conjugated double bonds.

 Each extension in this conjugated system reduces the energy required for electrons to transition to higher energy states, allowing the molecule to absorb visible light of progressively longer wavelengths. Lycopene absorbs all but the longest wavelengths of visible light, so it appears red. Conjugated bonds of lycopene molecule gives ability to act as an antioxidant and make it more efficient for the use of human health.

Plants and photosynthetic bacteria naturally produce all-trans lycopene, but a total of 72 geometric isomers of the molecule are sterically possible. When exposed to light or heat, lycopene can undergo isomerization to any of a number of these cis-isomers, which have a bent rather than linear shape. Different isomers were shown to have different stabilities due to their molecular energy (highest stability: 5-cis ≥ all-trans ≥ 9-cis ≥ 13-cis > 15-cis > 7-cis > 11-cis: lowest). In the human bloodstream, various cis-isomers constitute more than 60% of the total lycopene concentration, but the biological effects of individual isomers have not been investigated.

Fig: 1.1: Skeletal formula of all-trans lycopene

Lycopene is insoluble in water, and can be dissolved only in organic solvents and oils. Because of its non-polarity, lycopene in food preparations will stain any sufficiently porous material, including most plastics. While a tomato stain can be fairly easily removed from fabric (provided the stain is fresh), lycopene diffuses into plastic, making it impossible to remove with hot water or detergent. If lycopene is oxidized (for example, by reacting with bleaches or acids), the double bonds between the carbon atoms will be broken; cleaving the molecule, breaking the conjugated double bond system, and eliminating the chromospheres.

In the present investigation the amount of lycopene isolated from watermelon, tomato and papaya has been recorded and quantification of lycopene was done.

Need and Significance

A modern life style keeps away people from healthy diet. For healthy dietary habits one should increase the consumption of food products which are helpful to the prevention of  illness. Carotenoids are important to human because they have antioxidant activity and prevent free radicals from causing harm to the body, similar to other types of antioxidants such as Selenium and vitamins C and E. The most efficient carotenoid  antioxidant  is  lycopene.

Lycopene health benefits include treating neurological disorder, supporting immune system, fighting diabetes, treating  prostate cancer, promoting hair growth  and  slowing down ageing process.

Materials and Methodology

We studied three different fruits watermelon (citrulluslanatus), tomato (Solanumlycopersicum) and papaya (carica papaya).

 Isolation method: We made a paste separately of watermelon, tomato and papaya. In the laboratory weigh 100 gm. paste of each of the three fruits. 100 gm of sample of watermelon taken in a 250 ml beaker. Then warm the paste and add about 30 ml of warm (40C) benzene to it. Stir well and decant the benzene layer. Again add 30 ml warm benzene, stir and decant the benzene. This has been done about 5 times. Then distil off benzene and we got residue of Lycopene. Recrystallized residue by ether and weighed. 

Repeat the steps with other sample of tomato and papaya and recorded the observations. Identification test of the isolated Lycopene were performed using  concentrated sulphuric acid.

Result and Discussion

The yield of lycopene after recrystallization is shown in the table. All the samples give a significant difference in the lycopene content. Watermelon has a highest content i.e. 3.18 mg which is significantly more than tomato. Tomato and papaya have 2.72 mg and 1.14 mg lycopene content respectively.  Again both have a significantly different values. To identify the lycopene extracted, few crystals were dissolved in concentrated sulfuric acid and they impart a indigo blue colour to the solution as we add water to it, again turns to red colour. 

This test initially helps us to identify lycopene  in the residue. Crystals were purified by recrystallization from ether.

Table 1: Lycopene content in various fruits

S.No	Fruit	Weight (g)	Lycopene (mg/100g)
1.	Watermelon	100	3.18
2.	Tomato	100	2.72
3.	Papaya	100	1.14

Figure 1: Graph showing the lycopene content in various fruits

Findings

·         The  presence of lycopene content  is  identified  in the fruits such as  tomato, watermelon     and papaya.

·         The highest lycopene content  in  the  watermelon extract.

·       The fruits taken for this  project  proved  as a  good source of  antioxidant  could be used   as a raw material  in  drug formulation.

Conclusion

Results   of the studies showed that the  fruits  analyzed having  high concentration  of lycopene. In this study, the highest content of  lycopene was observed in watermelon. The second highest content was found in tomato and  the lowest content  was in papaya.

The results  of studies can be  improved  when  we use  different  solvents  in extraction process. In the above  discussed  procedure  benzene was used to extract  lycopene from watermelon, tomato and papaya.

References

·      Parveen Jamal, Iqrah Akbar, Yumi Z, Process development for maximum lycopene production from selected fruit waste and its antioxidant and  antiradical activity, Journal of food processing and technology, 1-7 (2016)

·      Dr.Komal  Chauhan, Dr. Sheel Sharma and Nidhi Agarwal,lycopene of tomato fame:Its role in health and disease,International journal of pharmaceutical science review and research,1(10), 99-115 (2011)