Chemical composition of seeds of four Bulgarian grape varieties

Temenuzhka Ovcharova,R Dimitrova,M Zlatanov

doi:10.1051/ctv/20163101031

Temenuzhka Ovcharova, R Dimitrova + Show 1 more

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https://doi.org/10.1051/ctv/20163101031

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Abstract

The composition of grape seeds from two white dessert (‘Bolgar’ and ‘Super ran Bolgar’) and two red wine Bulgarian varieties (‘Mavroud’ and ‘Shiroka melnishka loza’) was investigated. The content of proteins was established by Kjeldhal method and was found to be 6.3 – 8.9%. The content of carbohydrates - calculated as the difference of mean values: 100 - (amount in percentage of oil, moisture, protein and ash) - was 65.5 – 70.9%. The content of oil – by extraction with n-hexane - was 11.6 - 16.5%. The content of phospholipids was determined spectrophotometrically after isolation by chromatographic methods and was found to be 0.6 - 0.9%, including phosphatidylcholine, phosphatidylinositol and phosphatidic acids. The sterol content determined by gas chromatography was 0.3 – 0.4% while β-sitosterol (70.0 – 72.1%) and campesterol (18.5 – 19.9%) were the major components. In the phospholipids and sterol esters, saturated and monounsaturated fatty acids presented higher amount than the triacylglycerols. Fatty acids of sterol esters and phospholipids were determined by gas chromatography after isolation. The quantity of palmitic acid in the phospholipid fraction was 43.4 – 59.4%, the content of oleic acid was 9.0 – 14.0% and the content of linoleic acid was 10.0 – 24.5% while in the sterol esters, the predominant ones were mainly linoleic (40.7 – 53.8%), oleic (24.9 – 35.5%) and palmitic acids (13.0 – 16.7%). Linoleic (68.5 – 72.3%) and oleic acids (16.3 – 18.7%) were found to be the main components of the triacylglycerols. The tocopherol content varied from 67.7 mg kg-1 to 290.5 mg kg-1 where α-tocopherol (74.8 – 84.4%) was the predominant component.

Highlights

Rodriguez et al, 2005; Freitas et al, 2008; Kim et al, 2008; Lutterodt et al, 2011), a by-product ofGrape seeds comprise about 5% of the fruit weight (Choi and Lee, 2009) and more than 3 million tons of them are discarded annually worldwide (Fernandes et al, 2012)
The aim of the present study is to characterize the chemical composition of grape seeds, including proteins, carbohydrates, ash, the content and composition of biologically active substances such as phospholipids, sterols and tocopherols; as well as fatty acid profile of triacylglycerols, individual phospholipids and sterol esters of triacylglycerol fraction extracted from seeds of Bulgarian grape varieties with a view to estimate the values of the oil as functional food with therapeutical effect, salad oil and for preparing cosmetic products and the seeds for source of food supplements
These data were similar to the results reported earlier by Kamel et al (1985) and Mironeasa et al (2010) but higher than the percentages for other Bulgarian cultivars found by Licev et al (1974) as well as by Razuvaev (1980) which reported significantly lower quantities of carbohydrates (44.0 – 57.0%)

Summary

Introduction

Grape seeds comprise about 5% of the fruit weight (Choi and Lee, 2009) and more than 3 million tons of them are discarded annually worldwide (Fernandes et al, 2012) (in Bulgaria 10 000 – 20 000 tons annually). Grape seed oil is used for salad dressings, marinades, deep frying, flavoured oils, baking, massage oil, sunburn repair lotion, hair products, body creams, lip balm and hand creams (Akin and Altindisli, 2011). It is a good source of polyunsaturated fatty acids (PUFAs), vitamins and antioxidants.

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