Rosa rugosa Low Caloric Fiber Protein Preparations Rich in Antioxidant Flavanols and Ellagitannins.

Defatted seed residues after the extraction of rose oil have their potential not fully described in the existing literature. The aim of this study was to determine and characterize the components important for the human body that are found in Rosa rugosa defatted seeds, including dietary fibers, proteins, selected minerals, polyphenols and antioxidant activity. Rosa rugosa seeds defatted with CO2 in supercritical conditions are a rich source of dietary fibers (approx. 65%) and proteins (15%); their macronutrients include the following: Ca (175.9), Mg (83.9), K (199.2) and Na (3.5 mg/100 g). They also contain polyphenols, including flavanols (0.9%) and total ellagic acid (0.5%), and they exhibit antioxidant activity (143.8 µM TAEC/g). Tellimagrandin I and II and rugosin A were found in the extracts, and ellagitannins with a yet-indeterminate structure were also present. The seeds also contained ellagitannin derivatives-galloyl-HHDP-glucose and bis-HHDP-glucose-at the same time, and they are characterized by a low-fat content-0.4%. The energy value of defatted rose seeds is about half the energy value of popular seeds used in the food industry. The findings of the present study suggest that defatted rosehip seeds, the by-product of rosehip processing, could be an important source of bioactive components like dietary fibers, flavanols, ellagitannins and mineral compounds. Therefore, defatted rose seeds are very promising and require further research, because they can potentially be used as a natural source of chemopreventive agents.

Stability of ellagitannins in processing products of selected Fragaria fruit during 12 months of storage.

The aim of the study was to determine the stability of ellagitannins (ETs), ellagic acid, and conjugates (EAC) in unclarified juices and purees produced from two selected berries of the Rosaceae family, genus Fragaria. A total of 16 ellagitannins have been identified in the products. Stability studies were carried out for 1 year in three temperature variants: -20, 4, and 20°C (±2°C). The quantitative and qualitative determinations of ETs + EAC were performed every 3 months using the HPLC-DAD and LC-MS techniques. An important element of the research was also the determination of ETs transformations that occur in juices and purees during storage. The stability of ETs + EAC is primarily determined by the temperature and storage time as well as the matrix. After 1 year of storage at -20°C, the sum of ETs and EAC did not decrease in strawberry juice. On the other hand, the decrease was shown at the level of 30 and 20% at temperatures of 4 and 20°C, respectively. In strawberry purees, a decrease in ETs + EAC of 15-28% was recorded during storage in all three temperature variants. After 1 year, in wild strawberry juice, 20-50% of ellagitannin decreased, in puree the decrease in ETs + EAC concentration was 40-54%. With increasing temperature, the percentage of compounds with lower molecular weight increased-from 10 to 14% at temperatures of 4 and 20°C, respectively. At the temperature of -20°C, the proportion of low- and high-molecular-weight compounds remained stable in each case.

Lactic acid fermentation of osmo-dehydrated onion.

The aim of the study was to determine the effect of osmoconcentration in a sucrose and sodium chloride solution on the efficiency of lactic fermentation and the content of polyphenols and oligosaccharides in yellow and red onion varieties: Alonso, Hysky, Hystore, and Red Lady. In most cases, no negative effect of onion dehydration was noted on the growth or number of the bacteria tested. Osmotic dehydration of onions prior to lactic fermentation may positively modify the profile of lactic acid isomers by increasing the proportion of the L (+) isomer. The use of osmotic dehydration before fermentation did not adversely affect the content of polyphenols in the onions. Simultaneously, the loss of fructo-oligosaccharides was limited: 60 % of the initial fructo-oligosaccharide content was obtained using the Alonso cultivar and Levilactobacillus brevis 0944 for onion fermentation.

Rosa spp. Extracts as a Factor That Limits the Growth of Staphylococcus spp. Bacteria, a Food Contaminant.

Due to their richness of bioactive substances, rose hips are a valuable raw material for obtaining extracts with potential antimicrobial activity. The aim of the study was to determine the antagonistic potential of whole pseudo-fruit and flesh extracts of three Rosa sp. varieties against Staphylococcus spp. bacteria isolated as food contaminants. The biological material in this study consisted of seven strains of bacteria from the genus Staphylococcus. Two strains-Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis DSMZ 3270-were used as reference strains. The other five strains were food-derived isolates-S. epidermidis A5, S. xylosus M5, S. haemolyticus M6, S. capitis KR6, and S. warneri KR2A. The material was the pseudo-fruits of Rosa canina, Rosa pomifera Karpatia, and Rosa rugosa. The polyphenols were extracted from the fleshy part and the whole pseudo-fruit for all rose varieties. The tested preparations differed significantly in their polyphenol composition. The sum of polyphenols ranged from 28 862 to 35 358 mg/100 g of lyophilisate. The main groups of polyphenols found in the preparations were flavanols and ellagitannins. All of the tested extracts inhibited the growth of staphylococci at a concentration of 500 mg/mL. Rosa rugosa fruit extract showed the strongest antimicrobial properties among the studied extracts. For all the strains, the growth inhibition had a diameter of 20.3-29.0 mm. Moreover, six out of the seven tested strains showed the highest inhibition with the use of this extract. The MIC of rose extracts was in the range of 3.125-500 mg/mL and was strictly dependent on the bacterial species, the species of the rose, and the part of the fruit from which the extract was obtained. Correlations were assessed between the main groups of polyphenols in the extracts and their inhibition of bacterial growth. In the case of pseudo-fruit extracts, the inhibitory effect on bacterial growth positively correlated with the content of ellagitannins, and this effect was observed for almost all the tested strains. The results presented herein follow the current trend of minimising the use of chemical preservatives in food; from this point of view, rose extracts are very promising.

Transfer of ellagitannins to unclarified juices and purees in the processing of selected fruits of the Rosaceae family.

The present study investigated the transfer of ellagitannins (ETs) from selected berry fruits of the Rosaceae family to the products of their processing - unclarified juices and purees, as well as ET retention in pomace. Percentage distribution was calculated not only for total ETs, but also separately for each ET identified by HPLC-MS. In the case of all fruits tested, ET transfer to purees was two to six times greater as compared to juices. The content of oligomeric ETs in juices was five times lower than that of low molecular weight compounds, while the transfer of high molecular weight compounds (>1569 Da) to purees ranged from 56% to 87%. An increase in molecular weight from 1569 Da to 3740 Da resulted in a fivefold decrease in ET transfer for raspberry juice, a twofold decrease for blackberry and wild strawberry juices, and a fourfold decrease for strawberry juice.

Anticandidal activity of Lactobacillus spp. in the presence of galactosyl polyols.

Yeasts have a substantial impact on the contamination and loss of food. In this study, we applied bacteria of the genus Lactobacillus as natural biopreservatives. Anticandidal strains of bacteria were selected from among 60 strains of bacteria grown which were each with nine polyols or galactosyl polyols. Polyols and galactosyl polyols can act as prebiotics for lactic acid bacteria and can enhance the antifungal properties of bacteria by affecting their metabolism. The galactosyl polyols significantly improved the anticandidal activity of most of the bacteria we tested. Based on the screening, the most promising strains of bacteria were selected, and their metabolites (both primary and secondary) and enzymatic activity were characterized in the presence of polyols and galactosyl polyols. The qualitative and quantitative content of bacterial metabolites depended both on the bacterial strain and the type of culture medium. A wide variety of antifungals produced by bacteria, such as fatty acids, hydroxy fatty acids, and other acidic products with potential antagonistic activity (phenyllactic acid or hydroxyphenyllactic acid) were detected. The bacteria produced a high concentration of phenyllactic acid in the presence of galactosyl polyols (up to 84.3 mg/L). This finding could suggest that this metabolite may have a significant impact on the antifungal properties of lactobacilli against yeast. Galactosyl polyols influenced the enzymes involved in the synthesis of fatty acids and hydroxylated fatty acids (esterase lipase, acid phosphatase, and α-glucosidase). The mechanism of the antifungal effect of lactobacilli may be based on the synergistic effect of their primary and secondary metabolites, in particular phenyllactic acid.

Protocatechuic acid and quercetin glucosides in onions attenuate changes induced by high fat diet in rats.

Yellow onion waste from industrial peeling was used to obtain three pure preparations: protocatechuic acid (PA), quercetin diglycosides (QD) and quercetin monoglycosides (QM). PA contained 61% protocatechuic acid, QD contained 35% quercetin diglucosides, mainly quercetin-3,4'-diglucoside, and QM contained 41% monoglucosides, mainly quercetin-4'-glucoside. The highest antioxidant activity was shown by PA. The effects of preparations on the digestive functions of the gastrointestinal tract of rats as well as the biochemical parameters and antioxidant capacity of the blood in model research on Wistar rats sustained by a high-fat diet were assessed (5 groups per 8 animals). The results of the present experiment showed that different onion phenolic preparations differently modulated the enzymatic activity of faecal (P < 0.001) and caecal (P < 0.001) microbiota. For instance, the QD preparation but not QM efficiently reduced the faecal and caecal bacterial ß-glucuronidase activity. Both protocatechuic acid and quercetin monoglycosides showed a beneficial effect by regulating blood lipids (reduction of TC (P < 0.001) and TG (P < 0.001), non-HDL increase in HDL (P < 0.001)), thereby lowering the risk factors for atherosclerotic lesions AI (P = 0.038) and AII (P = 0.013). In addition, onion phenols showed a strong antioxidant effect, however, with a different mechanism: protocatechuic acid via serum ACL (P = 0.033) increase and hepatic GSSG (P = 0.070) decrease, QM via ACW (P < 0.001) increase and hepatic TBARS (P = 0.002) decrease, and QD via serum ACW increase and hepatic GSSG decrease. It can be concluded that onion polyphenols with a lower molar weight, i.e. QM more preferably affect the blood lipid profile than QD. However QD more efficiently reduced the faecal and caecal bacterial ß-glucuronidase activity.

The effect of osmotic dehydration on the polyphenols content in onion.

BACKGROUND: The onion is one of the most popular vegetables in the world, often used in the food industry. The purpose of this work was to determine the effect of osmotic dehydration of onions after storage in solutions containing various amounts of sucrose and sodium chloride on the course of osmoconcentration and the level of polyphenols in the dehydrated vegetables. The results could be useful to define the dehydration conditions under which a product retains the highest content of these health-promoting substances. METHODS: Onions var. Robusta were used. The vegetables were stored for six months at 0°C (air relative humidity 75–80%). They were cut into quarters just before dewatering. Samples of 20 ±1 g were dehydrated for five hours in a 40–60°Bx sucrose solution and a 5–15% NaCl solution (25°C); the weight ratio of the sample to the solution was 1:5. The contents of polyphenols and dry matter were determined. RESULTS: The use of a mixture of two osmotic agents (sucrose, sodium chloride) was more effective in the increase of dry matter content than using only sucrose. Nearly 49% dry matter content in onion was obtained by using a 60% solution (50% sucrose + 10% NaCl) for five hours. The greatest differences in the content of total polyphenols occurred during the first hour. After this time, retention amounted to 48–90%, depending on the concentration of sucrose (40–60%) and sodium chloride (5–15%). The retention of diglycosides of quercetin (mainly quercetin-3,4’-diglucoside) was lower than that of monoglycosides (mainly quercetin-4’- -glucoside). Following dehydration in a solution containing 60% sucrose and 10% NaCl, after three hours, there was about one third of the initial amount of the above-mentioned compounds in onion. CONCLUSIONS: The increase in the concentration of the hypertonic solution, being a mixture of sucrose and sodium chloride, causes a reduction in the retention of total polyphenols in osmotically dehydrated onions. The smallest losses occur after applying a 40% sucrose solution with NaCl up to 10%.

Onion quercetin monoglycosides alter microbial activity and increase antioxidant capacity.

The effects on fermentation processes in the digestive tract, the biochemical parameters and antioxidant capacity of blood in rats fed high-fat diets with quercetin (Q) and quercetin with quercetin monoglycosides (Q+MQ) preparations obtained from onion waste were evaluated. Four groups of eight animals were fed for 4 weeks with a control diet (C), a high-fat diet (HF) and high-fat diets with 0.15% addition of Q and Q+MQ preparations. HF caused an increase in alanine transaminase (ALT), non-high-density lipoprotein (non-HDL) and the atherogenic index AII vs. C and a decrease in the proportion of HDL in total cholesterol (TC). Q and Q+MQ showed a tendency to moderate the values aspartate transaminase (P=.087), ALT (P<.05), TC (P=.068), non-HDL cholesterol (P<.05), triglycerides (P=.064) and the atherogenic index AII (P<.05). Q+MQ significantly increased the activity of α-glucosidase (P<.05 vs. HF), ß-glucosidase (P<.05) and ß-galactosidase (P<.05 vs. C and Q). Q increased activity of ß-glucosidase (P<.001 vs. C and HF). Both increased the activity of ß-glucuronidase (P<.05 vs. C and HF). Both increased the antioxidant capacity of the hydrophilic fraction in serum (P<.05 vs. C and HF), and Q enhanced that of the lipid fraction (P<.001). Q preparation contained 70% quercetin, and Q+MQ preparation contained 29% quercetin and 13% quercetin monoglycosides, mainly quercetin-4'-glucoside. Both exhibited high antioxidant capacity. Supplementation with Q and Q+MQ increased the enzymatic activity of the intestinal microbiota and the antioxidant capacity of blood and revealed a tendency to improve the blood lipid profile. MQ were particularly effective in stimulating the bacterial enzymatic activity.

Application of Transgalactosylation Activity of ß-Galactosidase from Kluyveromyces lactis for the Synthesis of Ascorbic Acid Galactoside.

In view of a commonly known beneficial role and low stability of ascorbic acid, many efforts are constantly undertaken to produce its improved derivatives. This paper presents results on the synthesis of ascorbic acid galactoside using transgalactosylation properties of ß-galactosidase from Kluyveromyces lactis and lactose as a donor of galactosyl moiety. The purpose of this study was to determine the influence of selected factors (concentration and molar ratio of substrates, amount of the enzyme preparation, pH of the solution, presence of different ions) on the course of transgalactosylation reaction. Research has shown that approx. 2.5% dry matter (d.m.; 12.7 g/L) of ascorbic acid galactoside is formed under favourable conditions (50% (w/v) substrates, sodium ascorbate and lactose at the molar ratio of 1.9:1, enzyme dose of 28,600 U/100 g lactose, pH = 7.0). The addition of Mg2+ or K+ ions to the reaction medium caused an increase in the final product content (even up to approx. 3.4% d.m., 17.2 g/L), while Na+ or Mn2+ had an adverse impact on the yield. The gathered data may be valuable for cosmetic or food industry.

Antifungal Activity of Lactobacillus pentosus LOCK 0979 in the Presence of Polyols and Galactosyl-Polyols.

The antifungal activity of Lactobacillus pentosus LOCK 0979 depends both on the culture medium and on the fungal species. In the control medium, the strain exhibited limited antagonistic activity against indicator food-borne molds and yeasts. However, the supplementation of the bacterial culture medium with polyols (erythritol, lactitol, maltitol, mannitol, sorbitol, xylitol) or their galactosyl derivatives (gal-erythritol, gal-sorbitol, gal-xylitol) enhanced the antifungal properties of Lactobacillus pentosus LOCK 0979. Its metabolites were identified and quantified by enzymatic methods, HPLC, UHPLC-MS coupled with QuEChERS, and GC-MS. The presence of polyols and gal-polyols significantly affected the acid metabolite profile of the bacterial culture supernatant. In addition, lactitol and mannitol were used by bacteria as alternative carbon sources. A number of compounds with potential antifungal properties were identified, such as phenyllactic acid, hydroxyphenyllactic acid, and benzoic acid. Lactobacillus bacteria cultivated with mannitol synthesized hydroxy-fatty acids, including 2-hydroxy-4-methylpentanoic acid, a well-described antifungal agent. Scanning electron microscopy (SEM) and light microscopy confirmed a strong antifungal effect of L. pentosus LOCK 0979.

Synthesis of the Galactosyl Derivative of Gluconic Acid With the Transglycosylation Activity of ß-Galactosidase.

Bionic acids are bioactive compounds demonstrating numerous interesting properties. They are widely produced by chemical or enzymatic oxidation of disaccharides. This paper focuses on the galactosyl derivative of gluconic acid as a result of a new method of bionic acid synthesis which utilises the transglycosylation properties of ß-galactosidase and introduces lactose as a substrate. Products obtained in such a process are characterised by different structures (and, potentially, properties) than those resulting from traditional oxidation of disaccharides. The aim of this study is to determine the effect of selected parameters (concentration and ratio of substrates, dose of the enzyme, time, pH, presence of salts) on the course of the reaction carried out with the enzymatic preparation Lactozym, containing ß-galactosidase from Kluyveromyces lactis. Research has shown that increased dry matter content in the baseline solution (up to 50%, by mass per volume) and an addition of NaCl contribute to higher yield. On the other hand, reduced content of the derivative is a result of increased pH from 7.0 to 9.0 and an addition of magnesium and manganese salts. Moreover, exceeding the ß-galactosidase dose over approx. 35 000 U per 100 g of lactose also leads to reduced yield of the process. The most favourable molar ratio of sodium gluconate to lactose is 2.225:0.675. Depending on the conditions of the synthesis, the product concentration ranged between 17.3 and 118.3 g/L of the reaction mixture, which corresponded to the mass fraction of 6.64-23.7% of dry matter. The data obtained as a result of the present study may be useful for designing an industrial process.

Ellagitannins from Rubus idaeus L. Exert Geno- and Cytotoxic Effects against Human Colon Adenocarcinoma Cell Line Caco-2.

Ellagitannins possess several biological activities, including anticancer properties. The goal of the present study was to investigate the cyto- and genotoxic activities of a red raspberry ellagitannin preparation (REP) in the concentration range of 2.5-160 µg/mL, as well as that of the main individual raspberry ellagitannins, sanguiin H-6 (SH-6, 12.8-256 µM) and lambertianin C (LC, 9.3-378 µM), against human colon adenocarcinoma cell line Caco-2. The ellagitannin concentrations used in the study correspond to those found in foodstuffs containing raspberry fruit. REP, SH-6, and LC exhibited strong concentration-dependent genotoxic properties, inducing DNA damage ranging from 7.3 ± 1.3 to 56.8 ± 4.3%, causing double-strand breaks and oxidation of DNA bases. At IC50 (124 µg/mL) the REP affected the nuclear morphology and induced the apoptosis of Caco-2 cells. Because the REP has been found to possess chemopreventive activity, it can be used as a natural food additive to enhance the health benefits of foodstuffs.

Ellagitannins from Raspberry (Rubus idaeus L.) Fruit as Natural Inhibitors of Geotrichum candidum.

The paper presents the chemical characteristics of ellagitannins isolated from raspberry (Rubus idaeus L.) fruit and their in vitro and in situ antifungal activity against Geotrichum candidum LOCK 0511. The study investigated a complex preparation containing various raspberry ellagitannins at a concentration of 86% w/w, as well as pure lambertianin C and sanguiin H-6. The ellagitannin preparation was obtained by extracting raspberry press cake and purifying the extract using Amberlite XAD resin, while individual compounds were isolated by means of preparative HPLC. The complex preparation was analyzed for the content of ellagitannins, anthocyanins, and flavan-3-ols using HPLC and LC-MS. The antifungal activity of the complex ellagitannin preparation and the isolated ellagitannins was determined for the strain Geotrichum candidum. The MIC and MFC values (10.0 mg/mL and 30.0 mg/mL, respectively) were found to be the same for lambertianin C, sanguiin H-6, and the complex ellagitannin preparation. The fungistatic activity of the studied ellagitannin preparation at a concentration of 10 mg/mL, as determined by the poisoned medium method, was 65.2% following 6 day incubation of Geotrichum candidum, with the linear growth rate of only 16.2 mm/day. The corresponding parameters for the control sample were 0% and 56 mm/day, respectively. The study demonstrated both in vitro and in situ antifungal activity of raspberry ellagitannins against Geotrichum candidum.

Antifungal Activity of Lactobacillus sp. Bacteria in the Presence of Xylitol and Galactosyl-Xylitol.

Lactic acid fermentation is a natural method of antimicrobial food protection. Antagonistic activity of Lactobacillus sp. bacteria, taking part in this process, is directed mainly against the same or other microorganisms. In this work we determine the impact of the presence of xylitol and galactosyl-xylitol on the antagonistic activity of 60 Lactobacillus sp. strains against indicator molds (Alternaria alternata, Alternaria brassicicola, Aspergillus niger, Fusarium latenicum, Geotrichum candidum, and Mucor hiemalis) and yeasts (Candida vini). We used double-layer method to select antifungal strains of Lactobacillus bacteria and poisoned medium method to confirm their fungistatic properties. Additionally, we examined the inhibition of Alternaria brassicicola by Lactobacillus paracasei LOCK 0921 cultivated with xylitol or galactosyl-xylitol directly on wild cherries. The presence of xylitol and its galactosyl derivative led to increase of spectrum of antifungal activity in most of the studied plant-associated lactobacilli strains. However, no single strain exhibited activity against all the indicator microorganisms. The antifungal activity of Lactobacillus bacteria against molds varied considerably and depended on both the indicator strain and the composition of the medium. The presence of xylitol and galactosyl-xylitol in the growth medium is correlated with the antifungal activity of the studied Lactobacillus sp. bacteria against selected indicator molds.

Effects of Lactofermented Beetroot Juice Alone or with N-nitroso-N-methylurea on Selected Metabolic Parameters, Composition of the Microbiota Adhering to the Gut Epithelium and Antioxidant Status of Rats.

An objective of this work was to assess the biological activity of beetroot juice (Chrobry variety, Beta vulgaris L. ssp. vulgaris), which was lactofermented by probiotic bacteria Lactobacillus brevis 0944 and Lactobacillus paracasei 0920. The oxidative status of blood serum, kidneys, and liver of rats consuming the fermented beetroot juice were determined. The experimental rats were divided into four groups on diet type: Basal diet, basal diet supplemented with fermented beetroot juice, basal diet and N-nitroso-N-methylurea treatment, and basal diet supplemented with fermented beetroot juice and N-nitroso-N-methylurea treatment. Mutagen N-nitroso-N-methylurea, which was added to diet in order to induce aberrant oxidative and biochemical processes and disadvantageous changes in the count and metabolic activity of the gut epithelium microbiota. The nutritional in vivo study showed that supplementing the diet of the rats with the lactofermented beetroot juice reduced the level of ammonia by 17% in the group treated with N-nitroso-N-methylurea. Furthermore, the positive modulation of the gut microflora and its metabolic activity was observed in groups of rats fed with the diet supplemented with the fermented beetroot juice. A concomitant decrease in the b-glucuronidase activity was a consequence of the gut epithelium microbiota modulation. The antioxidant capacity of blood serum aqueous fraction was increased by about 69% in the group of rats treated N-nitroso-N-methylurea mixed with the fermented beetroot juice and N-nitroso-N-methylurea versus to the N-nitroso-N-methylurea treatment, whereas the antioxidant parameters of the blood serum lipid fraction, kidneys, and liver remained unchanged.

Influence of thermal treatment on the stability of phenolic compounds and the microbiological quality of sucrose solution following osmotic dehydration of highbush blueberry fruits.

BACKGROUND: Osmotic dehydration is a process of the partial removal of water which is based on immersion of material having cellular structure in a hypertonic solution. Osmotic dehydration is used as a pretreatment for the dehydration of foods before they are subjected to further processing such as freezing, freeze drying, vacuum drying. Management of spent syrup is one of the most important problems related to osmotic dewatering. Osmotic solutions are heavily polluted with of carbohydrates, remains of the dehydrated material and microorganisms. The aim of this study was to determine the effect of thermal treatment on the content of phenolic compounds and the microbiological quality of sucrose solution used in 15 cycles of osmotic dehydration of highbush blueberry (Vaccinium corymbosum L.) fruits. MATERIAL AND METHODS: The tested material was 65.0 ±0.5°Brix sucrose solution used for 15 cycles of osmotic dehydration of highbush blueberry (Vaccinium corymbosum L.). Osmotic dehydration was conducted at 40°C for 120 min using fruits previously subjected to enzymatic pretreatment. The thermal treatment of sucrose solution was conducted at 70, 80, 90, 100 and 115°C for 20, 40 and 60 s. The sucrose solution was analysed in terms of total polyphenols, particular polyphenols using high performance liquid chromatography and microbiological analysis was subjected. RESULTS: Thermal treatment at 70-115°C for 20 s caused degradation of 8.5% to 12.7% of polyphenols, while as much as 23.1% of polyphenols were degraded at 115°C after 60 s. The present paper proposes heating parameters that are optimal from the point of view of phenolic compound retention and microbiological quality: thermal treatment of syrup at 100°C for 40 s. Under these conditions, total polyphenols retention was 94.5%, while the retention of individual phenolic compounds varied from 89.2% to 37.2%, and that of flavan-3-ols amounted to 89.5%. The studied manner of syrup treatment eliminated the problem of syrup contamination with yeasts and molds (reducing their levels to less than 1 CFU/mL).

Osmotic Concentration of Gooseberry Fruits - The Influence of Temperature, Time and Pretreatment Methods on Mass Transfer and Total Polyphenol and Organic Acid Content.

The objective of the study is to assess the influence of temperature, time and enzymatic pretreatment on the osmotic concentration of gooseberry fruits (cultivar Bialy Triumf). The fruits were osmotically concentrated in a sucrose solution at 65 °Brix and 40 to 70 °C for 5 to 240 min. Two experimental procedures were employed. In the first procedure, prior to concentration the fruits were immersed in the solution containing lipolytic enzymes, and then in the solution containing pectinolytic enzymes. In the second procedure, pectinolytic enzymes were added to the sucrose solution. The kinetics of the osmotic concentration was studied based on the changes in dry matter content, water loss, and solid gain. Higher temperature and longer process time led to higher values of the mentioned parameters. After 1 h of concentration at 40 °C, dry matter content was 13.9%, while at 70 °C it was 20.4%. The use of pectinolytic enzymes during osmotic concentration resulted in higher effectiveness of the process. After 2 h of concentration with the use of pectinolytic enzymes, solid gain was seven times higher than that in the control sample. Enzymatic treatment with lipase and pectinase before concentration also increased solid gain during osmotic concentration (up to twelve times after 2 h at 40 °C). The lower processing temperature, the higher retention of phenolic compounds in fruits was observed. The retention of phenolics was the highest at 40 °C (92.2% at 2 h). Among organic acids (malic, shikimic and citric), the highest retention was exhibited by citric acid; at 1 h of concentration, its fraction in the obtained fruit syrup content was from 95.9 to 83.1% as compared to the starting material.

Antagonistic activity of lactic acid bacteria as probiotics against selected bacteria of the Enterobaceriacae family in the presence of polyols and their galactosyl derivatives.

Probiotic lactic acid bacteria were grown on erythritol, xylitol, sorbitol or lactitol and produced various derivatives: gal-erythritol, gal-xylitol, and gal-sorbitol as prebiotics. Galactosyl derivatives of erythritol, xylitol and sorbitol were metabolised by Lactobacillus spp. This resulted in their antagonistic activity against the test microflora. No activity was observed in the presence of xylitol and erythritol. Gal-sorbitol obtained by enzymatic transglycosylation from lactose had the same abilities of inducing the antagonistic activity of lactic acid bacteria that lactitol had.