ECONTECHMOD.ECONTECHMOD. AN AN INTERNATIONALINTERNATIONAL QUARTERLY QUARTERLY JOURNAL JOURNAL – 2018, – 2018, Vol. Vol. 07, No.07, No.1, ?? 1,–?? 5–9

Linguistic consultant: Małgorzata Wojcieszuk Typeset: Adam Niezbecki Birch concentrate as a potential modern food product Cover design: Hanna Krasowska-Kołodziej Maciej Bilek1, Jarosław Wawer2, Wojciech Szwerc3, Katarzyna Słowik3, Stanisław Sosnowski1

1 Department of Food and Agriculture Production Engineering, Faculty of Biology and Agriculture, University of Rzeszów, Poland ,Zelwerowicza 4, PL 35 601 Rzeszów, Poland

2 Department of Physical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Poland Narutowicza 11/12, PL 80 233 Gdańsk, Poland 3 Chair of Chemistry, Faculty of Pharmacy, Medical University of Lublin, Poland

Chodźki 4a, PL 20 093 Lublin, Poland e-mail: [email protected], [email protected], [email protected], [email protected]

All the articles are available on the webpage: Received:Received: February ???? 17, 15, 2018; 2018; Accepted: Accepted: ????? March 07, 01, 2018 2018 http://www.pan-ol.lublin.pl/wydawnictwa/Teka-Motrol.html

Abstract. This paper presents concentrate acid) into birch tree sap and the simultaneous addition of

obtained by the method. It is a chemical preservative, e.g. potassium sorbate, which All the scientific articles received positive evaluations by independent reviewers characterized by sweet taste, high content of minerals and extends the shelf life to at least one month, regardless of

no risk to consumers in terms of content of heavy metals the temperature conditions of storage [10, 17]. In case of standardized in the European Union food legislation. This such a composition, however, it is necessary to introduce beverage has all the features of a modern food product, sweetening, taste-improving additives that are necessary i.e. it has an attractive taste, is obtained using new to balance the acidic taste of citric acid [30, 35]. From the technology, meets the clean label requirements and can be nutritional point of view, the most preferred addition classified as a superfoods product. seems to be lactic acid, which, according to the food law Key words: birch tree sap, reversed osmosis, new in the category of liquid foodstuffs, can be used as an technologies, clean label products, nutritional value. additive to fruit . However, in the wide production ISSN 2084-5715 practice, this substance is also used as an addition to carbonated beverages, , and a very wide range INTRODUCTION of fruit and vegetable preserves [22]. As a natural product of processes occurring in the human body, it enjoys a The consumption of raw tree sap is deeply rooted in wide acceptance of consumers, also in the groups very the tradition of many countries in Europe, Asia and North radically oriented against highly-processed food [28]. It

America [31, 37]. Unfortunately, this form of use of the should also be emphasized that lactic acid not only

birch tree sap – and tree saps in general – is limited by enhances the taste, but also has a number of health-

their perishable character. It is valid usually about one day promoting properties. Among others it promotes the Editorial at room temperature and a few days under refrigeration absorption of minerals, such as calcium and iron, supports © Copyright by University of Engineering and Economics in Rzeszów 2018 conditions [8]. Birch sap can also be processed, most the action of antioxidant compounds and has a © Copyright by Lviv Polytechnic National University 2018 often into birch , [26] or into pasteurized, sweetened bactericidal effect [22]. beverages [21]. Regardless of the character of these As it has been presented, the formation of non- technological treatments, the processing is always high- pasteurized birch sap-beverages requires the introduction temperature, which changes the original composition of of at least two additives, i.e. food acid and a sweetening birch sap. Meanwhile, folk medicine and the results of the additive. Meanwhile, the consumer trend, gaining more Editorial Office Address latest scientific research have indicated numerous pro- and more followers and trending the aspect of modern Wyższa Szkoła Inżynieryjno-Ekonomiczna w Rzeszowie health benefits of raw unprocessed birch sap [29, 32, 39]. food industry promotes the clean label idea. Basically, it ul. Miłocińska 40, 35-232 Rzeszów For this reason, we have started to develop non- postulates the maximal limitation of food additives use, e-mail: [email protected] perishable, unpasteurized birch sap-based beverages. especially of chemical preservatives and added [33]. The addition of the citric acid and as taste- However, in case of birch sap, the possibility of improving additives seems to be the most promising implementation of the clean label idea on a scale other method of extending the shelf life of birch sap under than industrial [6, 20] seems to be difficult. New refrigeration conditions [7, 36]. Another option is the possibilities, however, have been opened by a recently Edition 200+16 vol. introduction of food acids (such as citric, lactic and malic described simple apparatus for the concentration of birch 6 2 M. BILEK, J. WAWER, W. SZWERC, K. SŁOWIK, S. SOSNOWSKI tree sap using reversed osmosis (RO) [38]. Until now, this Table 1. Physical parameters of the birch sap and of the new technology has been used in food industry as one of products of reverse osmosis (RO) process the stages of birch syrup production [25]. Birch sap Parameter Birch sap Permeat Thanks to the aforementioned solution, the healthy concentrate composition of birch sap is preserved. Also, a product Refraction value with a distinctly sweet taste is gained, in contrast to birch [°Brix] 0.9±0.0 2.6±0 0±0 tree sap, the taste of which is unattractive to consumers ±SD (n=3) and defined as similar to water [23]. It should be Electrolytical particularly emphasized that the improvement of conductivity 610±0 1530±0 10±0 organoleptic properties, i.e. obtaining a clear taste so [µS/cm] desired by the modern consumer, is therefore not ±SD (n=3) achieved due to the addition of the taste-improving pH ±SD (n=3) 6.8±0 6.4±0 5.6±0 additives, but through the use of a reverse osmosis Dry matter process and a significant increase in the concentration of 0.849±0.012 2.557±0.071 0.016±0.002 [%] ±SD (n=3) naturally occurring .

The aim of this study was to assess the health- The content of minerals is considered as the most promoting properties as well as health safety of the birch important nutritional feature of birch sap. The content of sap concentrate, obtained by the reverse osmosis. copper, zinc and manganese is very high from the point of

view of the nutritional norms. The content of other important

minerals, such as calcium or magnesium, is low [5, 11, 13, 14]. MATERIAL AND METHODS The concentrations of minerals in the tree sap and in

the RO products obtained in the present work are Birch sap collection. Tree sap of silver birch (Betula presented in Table 2. pendula Roth.) was collected in Łukawiec village

(50.097559, 22.168178), in accordance with the Table 2. The content of minerals in the birch tree sap and suggestions of commonly available indications [40], i.e. in the products of the reverse osmosis process the collection took place by the drilling technique, using Birch sap a drill bit with the diameter of 16 mm, to the depth of 4-5 Mineral Birch sap Permeat concentrate cm, on the southern sides of tree trunks. The tree sap was Sodium collected simultaneously from four trees, placed in one [mg dm-3] 0.73±0.01 18.8±1.7 0.381±0.004 container and then frozen. ±SD (n=9) Measurements of the physical and chemical Potassium parameters of birch sap as well as of the products of [mg dm-3] 90.7±1.6 302.6±6.2 4.04±0.1 the reverse osmosis process. Thawed birch sap was ±SD (n=9) concentrated using the apparatus described in detail in our Copper previous publication [38]. The physical parameters of -3 birch sap, concentrate and permeate were tested using the [µg dm ] 11.76±0.55 199.3±1.3

one liter of sap [%] of sap liter one obtained can be referenced to the maximum level set by -3 0 the Polish law for drinking water at 20 µg dm [34]. Fortunately the content of this heavy metal does not Covering of RDA/AI for minerals with with minerals for RDA/AI of Covering increase in the birch sap concentrate compared to the sap. The high concentration of nickel recorded in the sap Birch sap Birch sap concentrate Permeate collected in the village of Łukawiec confirms our earlier thesis that birch tree sap should always be examined in Fig. 1. The percentage implementation of nutritional terms of heavy metals content before processing and norm for an adult woman for minerals in one liter of birch consumption [15]. tree sap and the products of the reverse osmosis process. Birch sap concentrate as a modern food product, Recommended Dietary Allowance norm for zinc, obtained using the so called new technology. In this calcium, magnesium, iron and copper, Adequate Intake work birch sap concentrate has been presented. It is norm for manganese, sodium and potassium. characterized by sweet taste and meets all the latest trends in the food industry as well as the image of The content of heavy metals is the determinant of the modern foodstuff with high nutritional value. In addition health safety of birch sap consumption. In our earlier to meeting the health safety requirements [18] and studies, we did not find concentrations of heavy metals in implementing the above-mentioned clean label idea [33], birch sap which would be dangerous in relation to the the concentrate described is obtained using a relatively maximum levels for various raw materials of plant origin new technology in the field of food industry, i.e. reverse [4, 12, 15]. osmosis [39]. The popularity and practical application of new Table 3. The content of heavy metals in birch tree sap and technologies in food industry has been gradually the products of the reverse osmosis process increasing, while the foodstuffs obtained through them Birch sap Heavy metal Birch sap Permeat have enjoyed rising sales [1, 27]. The presented birch sap concentrate concentrate is characterized by a very high content of Lead minerals. This fact can be regarded as a distinctive feature -3 [µg dm ]