Viability of lactic acid bacteria in polyphenol-enriched fermented milks

The enrichment of probiotic dairy products with polyphenol extracts from different plant origins is a good approach to enhance the beneficial health effects of functional foods. The aim of the present study was to evaluate the effect of rose (Rosa damascena Mill.) petals polyphenol extract (RPPE) fortification on the lactic acid production and the viability of Lactobacillus delbrueckii subsp. bulgaricus S19 (Lb. bulgaricus), Lactobacillus rhamnosus YW (Lb. rhamnosus) and Streptococcus thermophilus S13 (S. thermophilus) in fermented milk samples during refrigerated storage. The fermented milk samples with RPPE (samples R1 and R2) and without RPPE (samples K1 and K2) were stored at 4 ± 2°C for 15 d. The results for physicochemical parameters showed a constant decrease in the pH values from 4.35 ± 0.04 to 3.99 ± 0.03 and an increase in the lactic acid concentration from 8.68 ± 0.17 g/L to 11.45 ± 0.26 g/L, respectively. The residual lactose concentration in the controls (K1 and K2) and supplemented samples (R1 and R2) at the end of the refrigerated storage was about 32.0 ± 0.24 g/L. Good survival of probiotic strains of lactic acid bacteria was observed. The results show that on the 15th day of refrigerated storage, the total count of lactic acid bacteria remains high - about 2.8 × 108 CFU/ml. Thus, RPPE could be used as a functional ingredient in fermented milk production

Application of NIR spectroscopy and chemometrics in quality control of wild berry fruit extracts during storage

Extracts of wild berry fruits (Bilberry, Cranberry, Raspberry and Strawberry) were analysed using the near infrared spectroscopy (NIRS). NIRS can be used quantitatively and qualitatively to detect, identify, and qualify raw materials like berry fruits and to control their quality. The spectra of fruit products were measured by diffuse trans-reflectance and raw spectra were used for chemometric analysis. The range of NIR used in this research was 904–1699 nm with the aim to use the potential of near-infrared spectroscopy to detect differences between berry-fruits themselves, differences between the sample based on the preparation procedure as well if it is possible to detect the staleness of the samples (fresh and one month old). NIR is a fast and non-destructive analytical method that in association with chemometric modelling becomes a powerful tool for application in food industry. The chemometric methods applied to the recorded NIR data were classification analysis based on principal component (PC) scores and partial last squared regression (PLSR) model. Analyses of the spectrums reveals changes in specific wavelengths of 904-1181 nm that are related to the 3rd CH overtone and 2nd overtone of the OH stretch of H2O as well as in the range of 1434- 1635 nm which correspond to C–H combinations and the 1stovertone of the bonds. The simple PLS regression showed that the influence of the storage on the NIR spectra of samples is high (R2=0.79). This study showed that near infrared spectroscopy has potential to distinguish extracts based on unprocessed freshwild berry fruit extracts, sample preparation procedure and their quality decrease affected by the storage. All findings indicate the advisability of use of NIR for on-line monitoring of product quality and selection

Thermodynamic investigations of the copigmentation process between strawberry anthocyanins and rose petal polyphenols (Rosa damascena Mill.) at different temperatures

In this study the model systems between strawberry anthocyanins as pigment and rose polyphenols as copigment was investigated. The solutions were prepared from 1:2 to 1:10 pigment:copigment. The addition of increasing concentrations of rose petal polyphenols resulted in a gradual increase of hyperchromic effect. The absorption was determined at heating system from 20 to 50 oC and following cooling the same system from 50 to 20 oC. All calculated thermodynamic parameters were negative. The copigmentation reaction was determined as spontaneous, exothermic and thermally reversible

Concentration of Polyphenolic Antioxidants in Apple Juice and Extract Using Ultrafiltration

The aim of the present work was to study the potential of ultrafiltration with three polyacrylonitrile membranes (1, 10, and 25 kDa) to concentrate polyphenolic antioxidants in apple juice and extract. The permeate flux, total polyphenols, polyphenolic profile, phenolic acid content, and total antioxidant capacity were determined using the FRAP and DPPH tests, the content of water-soluble proteins during ultrafiltration was established, and the concentration factors and rejections were determined. The permeate flux decreased by increasing the volume reduction ratio and decreasing the molecular weight cut-off of the membranes. The concentration factor and rejection of polyphenolics increased with the increase in the volume reduction ratio (VRR) for all membranes and both liquids. The concentration and rejection effectiveness of the 1 kDa membrane was higher than those observed for 10 and 25 kDa during the ultrafiltration of the apple extract, while these values were comparable for 1 and 10 kDa during the ultrafiltration of the apple juice. The concentration factors and rejections of total polyphenols were higher in the extract than in the juice. Chlorogenic acid was the main compound in the polyphenol profile of apple juice. The total content of phenolic acids, determined by using HPLC, increased by 15–20% as a result of the membrane concentration, but the separation process did not significantly change the ratio between the individual compounds

Viability of lactic acid bacteria in polyphenol-enriched fermented milks

The enrichment of probiotic dairy products with polyphenol extracts from different plant origins is a good approach to enhance the beneficial health effects of functional foods. The aim of the present study was to evaluate the effect of rose (Rosa damascena Mill.) petals polyphenol extract (RPPE) fortification on the lactic acid production and the viability of Lactobacillus delbrueckii subsp. bulgaricus S19 (Lb. bulgaricus), Lactobacillus rhamnosus YW (Lb. rhamnosus) and Streptococcus thermophilus S13 (S. thermophilus) in fermented milk samples during refrigerated storage. The fermented milk samples with RPPE (samples R1 and R2) and without RPPE (samples K1 and K2) were stored at 4 ± 2°C for 15 d. The results for physicochemical parameters showed a constant decrease in the pH values from 4.35 ± 0.04 to 3.99 ± 0.03 and an increase in the lactic acid concentration from 8.68 ± 0.17 g/L to 11.45 ± 0.26 g/L, respectively. The residual lactose concentration in the controls (K1 and K2) and supplemented samples (R1 and R2) at the end of the refrigerated storage was about 32.0 ± 0.24 g/L. Good survival of probiotic strains of lactic acid bacteria was observed. The results show that on the 15th day of refrigerated storage, the total count of lactic acid bacteria remains high - about 2.8 × 108 CFU/ml. Thus, RPPE could be used as a functional ingredient in fermented milk production

Enzyme-Assisted Extraction of Polyphenols From Rose (Rosa Damascena Mill.) Petals

: The efficiency of enzyme-assisted extraction for the recovery of polyphenols from rose (Rosa damascena Mill.) petals was evaluated performing a simplex centroid experimental design for mixture with three components (pectinolytic, cellulolytic and hemicellulolytic preparation). The ternary enzyme combinations leaded to the highest contents of total polyphenols, reaching 43% higher average value as compared to the control (without enzymatic treatment) sample. Enzymatic treatments also enhanced (9−25%) the extractability of total anthocyanins. The results obtained demonstrate that enzyme-assisted extraction improves the recovery of polyphenolic antioxidants from rose petals, especially using ternary enzyme combinations, comprising pectinolytic, cellulolytic and hemicellulolytic preparation

Near-Infrared Spectroscopic Analysis of Total Phenolic Content and Antioxidant Activity of Berry Fruits

This study evaluates the feasibility of using near-infrared (NIR) spectroscopy as a rapid and environmentally friendly technique for validation and prediction of the total phenolic content (TPC) and antioxidant activity (AOA) indices (as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, inhibition time (IT) of the Briggs-Rauscher oscillating reaction, and relative antioxidant capacity (RAC)) of berry fruit extracts. The analysed berry samples originated from Croatia (blackberries, wild blueberries, raspberries, red currants and strawberries) and Bulgaria (wild blueberries, raspberries and strawberries). Principal component analysis and partial least squares (PLS) regression were used from the set of chemometric tools in distinguishing and validating the measured berry fruit extract. ANOVA and PCA showed no significant impact of the origin and freshness of the samples. PLS models were developed to validate the relationship of NIR spectra with TPC and AOA of berry fruits. Representativeness of the models was expressed with the R2 and the ratio of performance to deviation. Calculated R2 values were above 0.84 and the ratio of performance to deviation was between 1.8 and 3.1, indicating adequacy of the PLS models