The Technology of Micro-Powders from Pulp and Peel of Wild-Growing Rose Hips in Georgian Conditions

Varden Khvedelidze, Doctor of Technical Science, Professor

Dodo Tavdidishvili, Candidate of Technical Science, Professor

Manana Pkhakadze, Candidate of Technical Sciences, Professor

Akaki Tsereteli State University, Kutaisi, Georgia

The main requirements to the technology for processing rose hips consist in a maximum preservation of biologically active substance.

Rose hip is a seasonal product, so in medicinal agents it is recommended to use the dry products from hip rose pulp and peel, which are characterized by high nutritional values and biological stability during storage. Due to their small volumes, the powders are acceptable in transportation and production of medicinal agents.

Proceeding from the set goal, the object under study is represented by micro-powders of rose hips (Fructus Rosae) wild-growing in Georgian conditions.

The production cycle of hip rose micro-powders comprises dehydration and grinding.

The best result has been obtained in processing of fruits by activation method at a low temperature (up to 20-25 ^оС). The loss of C vitamin, whereupon, does not exceed 10-12%. We note that when applying existing technology (drying to 70 ^оС, relative air humidity – up to 50%) the loss of C vitamin exceeds 24-25%.

The process of producing micro-powders from rose hip is a significant factor for preservation of organoleptic, physio-chemical and other parameters, since they impact to the quality of the finished medicamentous means and food additives.

We have proposed an optimal technological scheme for producing powders from rose hips (Fig. 1).

According to this technology it is possible to produce micro-powders as from rose hips as a whole, so from its seeds and pulp with peel. To achieve this set goal it is also possible to use the powder from rose hip pulp and peel as a vitaminic filler.

Following the drying process in the conditions ov intensive air supply at a temperature of no more than 50 ^оС, the rose hips are cooled down, ground and subjected to separation, pulp and peel are separated from seeds. Then, in micro-grinder, there is formed the micro-powder with particle size of no more than 50 microns (75%). Then the micro-powder is passed through the sieve, weighted and packed.

Micro-powder produced from rose hip pulp and peel is a homogeneous bulk brown mass having moisture conent of no mre than 10-12%.

For determining the optimal expiry terms of rose hip processing products, there were conducted studies of dynamic changes in indicators of rose hip powder composition and microbiological parameters during 12-month storage. The powders were stored in a dry well ventilated area, where the necessary sanitary requirements were met: temperature - 18-20 ^оС, and air relative humidity – 60-70%.

The wieght content of humidity in rose hip peel and its pulp powder decreased 0,3%, but acidity after the period of 8 months increased by 10% (after the period of 12-month storage, acidity increased by 21%). The loss of C vitamin after the period of 8-month storage was 6,5%, but after 12-month period of storage it was 22,0%.

Fig. 1. Technological scheme for producing micro-powder from rose hip pulp and peel

The results of studies of powders mocroflora composition have shown that an increase in the number of microorganisms after the period of 12-month storage is slight and does not exceed the permissible normal standards envisaged by methodological and biological requirements during the fruit and berry raw materials processing.

The analysis of the performed studies has shown that the dry rose hip micro-powder is desirable to store no more than 8 months, since with long-term storage the loss of C vitamin goes up.

For chraracterizing the friability of rose hip pulp and peel micro-powders the followinf formula was used:

K_v = µd / 4α(1- sin β) = 1,371,

where, K_v – are friability criteria; α =400 kg/m³ – the volume weight of rose hip micro-powder; d = 43 x 1,5 = 65 microns; d – extrusion inner diameter and 1,5 – adaptation coefficient; α – initial shearing resistance; sin β = sin 31⁰ 20¹ – angle of shearing resistance.

Thus, K_v = 1,37>1 indicates high friability of rose hip pulp and peel micro-powder.

In an object under study we have determined the content of: lipids, ascorbic acid, dry matters – in compliance with standards; proteins – by using Kjeldahl analyzer (BUCHI К-424, Switzerland); flavonoids – by using GF XI; carbohydrates, C vitamin and organic acids – by method of high-performance liquid chromatography (HPLC); carotenoids – by spectrophotometric method; the content of lipids – by thin-layer chromatography; fatty acid content of lipids – by method of chromatography using chromatograph “Carlo Erba Strumentazione”, HRGC 5300 Mega Series (Italy) and integrator “C-R6A Chromatopac” (manufactured by “Shimadzu” Company); the content of sterols – by HPLC method; dietary fibers – by fermentation-gravimetric method; macro- and micro-elements - by atomic-adsorption method, accordingly.

Total phenol compounds have been determined by using the Folin-Ciocalteu reagent, but the fractional content of flavonoids – by HPLC method.

For the technological purposes, it is important to determine chemical composition of micro-powder of air-dried wild-growing rose hip pulp and peel. The data are given below (the weight content, %):

Water	12,5
Proteins	4,1
Lipids	1,30
Ash	3,40
Dietary fibers: indissoluble dissoluble	33,36
	20,72
	12,64
Carbohydrates: glucose fructose sucrose	30,4
	14,2
	9,2
	7,0
Organic acids: malic acid citric acid	6,1
	0,65
	5,45

Evidently, the main fractions of rose hip micro-powder are the dietary fibers.

Lipid complex of rose hip pulp and peel micro-powders are represented as different groups, from which the main fractions are triglycerides.

The results of this study are given below (total %):

Polar lipids	12,5
Monoacylglycerols	3,2
Diacylglycerols	1,1
Sterols	7,4
Free fatty acids	19,0
Triacylglycerols	47,9
Waxes	3,0
Sterol ethers	2,6
Carbohydrates	0,7
Higher alcohols	2,8

The fractional contents of powder sterols from rose hip pulp and peel are given below (mg/kg):

Campesterol	24
Stigmasterol	13
β-sitosterol	419
24-ethyl-caprostanol	14
Cycloartenol	25
Cholesterol	29

The main fraction of rose hip powder sterols is represented by β-sitosterol.

The rose hip powder is a source of significant physiological-functional ingredients, such as C vitamin and carotenoids, which are characterized by high antioxidant activity. Their content in rose hip pulp and peel powders is as follows (mg/g): carotenoids – 0,25-0,26; vitamins - 13,0-14,0.

The rose hip pulp and peel micro-powder contains a significant amount of ascorbic acid and carotenoids, and consequently, is a good source of antioxidants.

Among biologically active substances of plant raw materials, of special importance are polyphenols, which have the different biological and antioxidant activity. It is shown that the rose hip pulp and peel micro-powders contain a large amount of polyphenolic compounds.

A quantitative difference of various phenolic compounds in rose hip powders present in equivalence in the total composition with trihydroxybenzoic acid pronounced in comparison with trolox, is conditioned by a composition.

Evaluation of antioxidant activity of rose hip pulp and peel powder by amperometric method (standard – in terms of trihydroxybenzoic acid) gives the values as follows: 14,30±0,65 mg/ g of dry matter.

The amount of polyphenols in the rose hip pulp and peel powders in equivalence with trihydroxybenzoic acid is 11,0 -11,2 mg/g of dry matter, but in equivalence with trolox - 40,5-41,0 mg/g of dry matter.

The amount a flavonoids in the rose hip pulp and peel powders in terms of rutin is 5,20 mg/g. Flavonoids in the rose hip powders are represented as: flavonoid aglycons – quercetin (1,3-11,5 mg/100g) and kaempferols (0,3-6,5 mg/100g); flavopnoid glycosides – rutin (3-4,9 mg/100g) and hyperoside (1-3 mg/100g); catechins in the total amount (58-78 mg/100 g) – such as epigallocatechin, catechin, epicatechin, epigallocatechin-gallate, gallocatechin-gallate and epicatechin-gallate.

For powders, it has been established that catechins prevail in the total amount of flavonoids.

Comparative studies of chemical composition of wild-growing rose hips in Georgia have shown that by the content of biologically active substances, the wild-growing rose hip is not inferior to sorted one that creates the prerequisites for developing its processing technology and applying in the production of pharmaceutical preparations and foods.