Anita Pichler

Volatile compounds of freeze-dried sour cherry puree affected by the addition of sugars

ABSTRACT The aim of this work was to determine the influence of the addition (5, 10, or 20 g/100 g) of different sugars (sucrose, maltose, or trehalose) prior to freeze-drying on the key volatile compounds of the sour cherry puree. The key volatile compounds of sour cherries were benzaldehyde, benzyl alcohol, and 2-hexenal. The results obtained for the samples with the addition of sugars were compared to the control sample, the sample without sugar addition. The control sample contained 3.92 mg/kg of benzyl alcohol, 856.61 µg/kg of benzaldehyde, and 15.58 µg/kg of 2-hexenal. Benzaldehyde, the compound described as the typical cherry volatile compound, was determined in the highest amount in the sample with the addition of 10 g/100 g of trehalose (937.51 µg/kg). The highest amount of 2-hexenal was determined in samples with the addition of 10 or 20 g/100 g of trehalose (17.45 and 18.96 µg/kg, respectively). All samples with the sugar addition had lower content of the benzyl alcohol than the control sample. Generally, samples with the addition of sucrose had the lowest amount of examined volatile compounds.

Influence of processing parameters on permeate flow and retention of aroma and phenolic compounds in chokeberry juice concentrated by reverse osmosis

ABSTRACT Reverse osmosis (RO) concentration of chokeberry juice, a rich source of polyphenols, at three different pressures (45, 50 and 55 bar) and two temperature regimes (with cooling and without cooling of the retentate) was studied. Concentration was carried out on a laboratory membrane unit with plates and frames on composite Alfa Laval membranes RO98pHt. Juice was concentrated till 24.9% of total soluble solids content (TSSC) . The permeate flow highly depended on processing parameters and varied from 15.19 ± 3.22 L/m2h at the beginning to 8.00 ± 2.21 L/m2h at the end of processes. Total phenolic compounds (4 anthocyanins, 2 flavonols and 2 phenolic acids) were determined by high performance liquid chromatography (HPLC). Twenty four volatile compounds were identified by gas chromatography with mass spectrometry (GC-MS) in chokeberry juice and concentrates. Processes at 50 and 55 bar with cooling proved to be the best in terms of chokeberry aroma, antioxidant activity and total phenolic compounds retention.

Influence of phenol and sugar interactions on antioxidant activity of pomegranate juice

Nowadays, people are focusing on antioxidant-rich food due to its beneficial effect on health. Thus, the goal of this study was to investigate the interactions between catechin, quercetin, and gallic acid in the presence of sugars (sucrose and trehalose) in complex food matrix such as pomegranate juice. Antioxidant activity (AOA) was measured by three different methods, DPPH and ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP). In this paper, fundamental differences among used AOA measuring methods were confirmed, which can be traced back to interactions occurring between phenols and/or sugars. Even though addition of individual phenols increased AOA of mixtures, in the majority of binary and ternary mixtures antagonistic effects were observed. Positive effect of sugar addition was more pronounced in binary mixtures but the results were highly dependent on used AOA method.

Influence of Sugars, Modified Starches and Hydrocolloids Addition on Colour and Thermal Properties of Raspberry Cream Fillings

Abstract This paper deals with the influence of the addition of sugars (sucrose, fructose and trehalose), modified starches (tapioca or waxy maize starch) and hydrocolloids (karaya or guar gum) on colour and thermal properties of raspberry cream fillings. In addition, the influence of the above-mentioned additives on the colour and thermal properties of raspberry cream fillings stored at room temperature over a period of 8 and 16 months was investigated. Results showed that the highest anthocyanin content and total phenolic content were detected in raspberry cream filling prepared with sucrose and trehalose in combination with guar gum. During storage, after 8 and 16 months at room temperature, anthocyanin content and total phenolic content decreased. Results also showed that the kind of sugar and added modified starches or hydrocolloids influenced the thermal properties of cream fillings. During storage, a decrease was observed in both freezing temperature as well as enthalpy of cream fillings.

Disaccharides: Influence on Volatiles and Phenolics of Sour Cherry Juice

The food industry is continuously developing ingredients, processing methods and packaging materials to improve the quality of fruit products. The aim of this work was to study the effect of sugars, a common ingredient in the food industry, on phenolics and volatiles of sour cherry juice. Sucrose, trehalose and maltose chemical isomers were chosen for this investigation. All sugars influenced the evaluated parameters. Samples with maltose addition had lower, while samples with sucrose and trehalose addition had higher anthocyanin content than the control sample. Generally, trehalose had a higher positive effect on volatiles with the desired flavor note.

Volatile profile of sour cherry puree as affected by sucrose and trehalose

ABSTRACT In this study, effect of sugars (sucrose and trehalose) and their amount on the volatile profile of sour cherry puree was evaluated. Results were compared to sour cherry puree without addition of sugars. Volatiles amount depended on type and amount of sugar. This indicated that the sugars showed an effect on flavour profile. Volatiles with the ethereal, alcoholic flavour note were present in the highest amount in the puree while with the addition of sugars, amount of those volatiles was lower. Sweet, floral volatiles were determined in higher amount when sugars were added in comparison to puree. Addition of sucrose did not have significant impact on the volatiles with sweet flavour note, while with addition of trehalose lower amount of those compounds were determined than in puree. Sweet, fruity and fresh, green volatiles were determined in higher amount in samples with the addition of sugars, especially when trehalose was added. Addition of sugar did not have impact on pungent volatiles.

Phenolics content and antioxidant activity of sour cherry extracts with sugar addition

Sour cherry puree was prepared with addition of sucrose or trehalose (5% and 10%). After stabilization of the mixture (puree with sugars), extracts were prepared and contents of phenolics and anthocyanin, polymeric colour percentage, and antioxidant activity were determined. Extracts were stored for 65 days at 4 °C. Control sample was extract of sour cherry puree without sugars. After extraction, extracts with 10% of sucrose or trehalose had higher phenolic content than the control sample. Anthocyanin content was higher in extracts with trehalose addition. During storage of extracts, samples with trehalose had higher retention of phenolic and anthocyanins than other samples. Addition of sucrose and trehalose as well as their amounts affected the stabilities of phenolics, anthocyanins, and antioxidant activity in sour cherry extracts.

Influence of disaccharides and pectin addition on antioxidant activity of phenolics

Food systems are very complex matrix and interactions between components have high impact on antioxidant activity of phenolic compounds. The aim of this study was to evaluate influence of addition of disaccharides, sucrose (S) and trehalose (T) or/and pectin (P) on antioxidant activity of catechin (C) or/and quercetin (Q) model systems after preparation and during storage at room temperature. Antioxidant activity (AA) was determined by DPPH, ABTS and FRAP method. Those methods have different mechanism of action thus different results were obtained. AA determined by DPPH method was higher in systems of C or Q when sugars or pectin was added than in systems of pure phenolics. In system CQ synergistic effect was observed, also when sugars or/and pectin was added the same effect was observed. During storage C system had the same AA, while Q system had lower AA. Systems C, Q and CQ with addition of sugars had higher AA. In systems with pectin addition in all combinations, higher AA was determined, except in the case of trehalose addition where very low AA was determined. AA determined by ABTS method in C systems with sugars or pectin decrease and increase in the case of Q system occurred in comparison to pure phenolics system. During storage, AA in systems C decreased while in systems Q increased. Systems CQ with pectin AA decreased while with sugars addition AA increased. AA determined by FRAP method was lower in systems of C or Q when sugars were added, and no synergistic effect was observed in system CQ. With addition of pectin, lower AA values were determined in all combinations. During storage, systems of C or Q and with sugars addition had lower AA. When pectin was added, C system had the same AA, and Q system higher. All combinations had lower AA. The results of our study showed the importance of food matrix composition as well as interactions that can occur between them.Ganoderma lucidum (GL) is a mushroom used as a traditional remedy for the treatment of various infections since ancient times. This study, was aimed to investigate antimicrobial activity potential of GL against Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Candida glabrata, Candida krusei, and Candida parapsilopsis. Furthermore, it was also aimed to evaluate the toxicity potential of GL. Antimicrobial activities were screened by using microbroth dilution method. With regard to toxicity studies, cytotoxicity was evaluated by using XTT method against NIH3T3 cell lines, whereas genotoxicity study was conducted by Ames MPF 98/100 mutagenicity assay. Obtained data indicated that minimal inhibitory concentration values of the extract against the tested microorganisms ranged from 200 to 400μg/ml. No cytotoxic activity was observed related to the Ganoderma lucidum administrations. However, results of the Ames test pointed out a genetic damage with metabolic activation against TA98. At the highest concentration (5mg/ml) the extract showed 2.71 fold increase over the baseline significantly. (p<0.05). In conclusion, in spite of significant antimicrobial effect potential, Ganoderma lucidum should be used carefully because of its genotoxicity potential.