Blueberry Pulp Research Articles

Production and biochemical characterization of freeze-dried blueberry juice from enzymatically processed berries

Production of freeze-dried juice semi-finished products is a promising direction in the technology of processing blueberries. This direction allows complex problem solving regarding seasonality of berry processing with optimization of logistics costs, extension of the geography of sources of raw material supply while preserving high sensory properties of a freeze-dried product. The main advantages of such a product are characteristics determining properties of fresh berries, including taste, color, aroma, nutritional and biological value. The aim of the study was the development of technological solutions to produce freeze-dried blueberry juice from enzymatically processed blueberry pulp, as well as determination of its biochemical characteristics. Chemical (titrimetric and gravimetric) methods and modern physico-chemical methods (HPLC, atomic absorption spectrometry, potentiometric and spectrophotometric methods) were used in the work. As a result of the performed investigations, parameters have been determined for the process of freeze-drying of native blueberry juice: freeze-drying temperature of –23 ±2 °С and pressure of 70–80 Pa, secondary drying at a temperature of 38–40 °С. Duration of the freeze-drying process was 16 hours until reaching the final moisture of 4%. It is shown that freeze-dried juice preserves all quality attributes of the native juice: taste, color and aroma. The native and freeze-dried blueberry juice was characterized by the chemical composition. The profile of flavonoids, anthocyans, phenolic and organic acids, composition of sugars, vitamins and minerals were studied. It has been established that the chosen parameters of freeze-drying ensure preservation of biologically active and minor substances at a level of no less than 77% of the initial content in the native juice. High preservation was demonstrated for quercetin and resveratrol. Losses were 9.6% for epicatechin, 13.7–23.0% for phenolic acids, and 14–22% for vitamins. As a result of juice processing by freeze-drying, an increase was noticed for the content of delphinidin-3-glucoside, cyanidin-3-arabinoside, cyanidin-3-glucoside by 20–35%. The proportion of cyanidin-3-galactoside + delphinidin-3-arabinoside decreased by 65% and that of delphinidin-3-galactoside by 2.85 times. A decrease in the content of macro-elements (up to 6.0%) was established in the freeze-dried juice; more noticeable losses were recorded for micro-elements (up to 14.8%). The results obtained show prospects of using the technology and chosen regimes of freeze-drying in production of freezedried blueberry juice. This technology combines a possibility of producing a manufacturable berry ingredient with maximum preservation of natural biologically active and minor components of berries for using in products of healthy nutrition.

Study of the stability of hydroelectrolytic sports beverages enriched with phenolic extract from jaboticaba peel or blueberry pulp

This study evaluated the impact of light exposure and storage conditions on sports beverages enriched with phenolic extracts from jaboticaba peel and blueberry pulp over a period of 91 days. The analysis encompassed various parameters, including microbial assessments, phenolic content, anthocyanin concentrations, color coordinates, and the stability of anthocyanin compounds. The results indicated that the applied heat treatment effectively maintained the beverages' microbiological safety, with the phenolic-rich extracts showcasing antimicrobial properties. Both beverages exhibited stability in total phenolic content. However, anthocyanin concentrations experienced significant reductions, although certain stabilizing factors, such as interactions between anthocyanins and phenolic compounds, contributed to color preservation. The study highlights the complexities of anthocyanin degradation and its effects on the color, flavor, and antioxidant properties of these enriched sports beverages.

Optimization of ellagic acid extraction from blueberry pulp through enzymatic hydrolysis combined with ultrasound-assisted organic solvent

The aim of this study was to optimize the technology used to extract ellagic acid from blueberry pomace. For single factor analysis, an enzymatic hydrolysis test showed that temperature, pH value and liquid-to-material ratio exhibited significant effects on ellagic acid content, as did three factors (the liquid-to-material ratio, ultrasonication time and temperature) for the ultrasound-assisted organic solvent method. A Box–Behnken design was applied for the enzymatic hydrolysis test and the ultrasound-assisted organic solvent method to determine the optimal combination scheme. For enzymatic hydrolysis, this scheme was 7:1 for the liquid-to-material ratio, 46 °C for the temperature of enzymatic hydrolysis and 4.9 for the pH value; under these conditions, an ellagic acid content of 1.96 mg/g (FW) was obtained. The optimal combination scheme for the ultrasound-assisted organic solvent was 2:1 for the liquid-to-material ratio, 65 °C for ultrasonication temperature and 82 min for the ultrasonication time, which produced ellagic acid contents of 7.92 mg/g (FW) and an extraction yield of 32.41%, respectively. The content and yield of ellagic acid in the extraction from blueberry pomace were greatly increased by combining enzymatic hydrolysis and an ultrasound-assisted organic solvent method. This study provides a theoretical reference for utilizing and developing blueberry pomace.

Bio-decolorization of synthetic dyes by a novel endophytic fungus Penicillium janthinellum LM5 from blueberry pulp

Synthetic dyes from textile, paper, leather, and plastic processing, etc. are the majority of the colored effluents and have a harmful impact on human health and environment. Dye biosorption through endophytic fungi will be a challenge. A new fungus isolated from blueberry pulp was identified morphologically and genetically as Penicillium janthinellum LM5. It was utilized for the biosorption of synthetic dyes by forming mycelium particles with efficient decolorization properties in the dye solution. The results of decolorization experiments exhibited that dye type, pH, temperature and time were the important factors and the best decolorization condition on Congo red was pH 6.0, 30 ℃ and 48 h. Moreover, LM5 can achieve 90% decolorization rate even under the high salt concentrations of 200 mg/mL. Based on spectral analysis, the decolorization of Congo red was mainly attributed to the biosorption of mycelium and its pellet structure. Additionally, the fungus adsorbed Congo red can be as an excellent electrode material with a long-cycle performance and stable capacitance property, being a good way for recycling. In summary, this research employed a novel dye treatment method with simultaneous culture and decolorization through an endophytic fungus LM5, being a promising biomaterial in the application of dye wastewater treatment.

Influences of subcellular Ca redistribution induced by γ irradiation on the fruit firmness of refrigerated blueberries

To investigate influences of intracellular calcium (Ca) redistribution induced by irradiation treatments on the firmness of refrigerated blueberries, 'Bluecrop' blueberry fruit were irradiated with gamma (γ) ray at doses of 0.5, 1.0, and 2.5 kGy and unirradiated fruit served as the control (CK). The influences of different irradiation doses on changes in intracellular Ca2+ fluorescence signals and subcellular Ca distribution were evaluated, as well as correlations of these changes with the firmness of refrigerated blueberry fruit. Results showed that irradiation treatment could induce blueberry pulp cells to produce Ca2+ fluorescence signals and increase the intracellular Ca2+ concentration. In addition, the greater the dose during irradiation, the more significant its effect. In the refrigeration period, the intracellular Ca distribution had no effect on fruit firmness of blueberries irradiated at 0.5 kGy. Whereas, irradiated at 1.0 and 2.5 kGy could make Ca content increase in cell walls and decrease in organelle and cytoplasm, thus promoting Ca accumulation in cell wall at early stage of storage. Subcellular Ca redistribution induced by irradiation at 1.0 kGy was not related to the fruit firmness of refrigerated blueberries, but irradiation at 2.5 kGy could promote the migration of intracellular Ca to cell wall, which exerted a positive effect on the fruit firmness of refrigerated blueberries.

Drying kinetics of blueberry pulp and mass transfer parameters: Effect of hot air and refractance window drying at different temperatures

Blueberry pulp was dried using hot air (HA) and refractance window (RW) methods at 55–95 °C, the drying kinetics were described by the Page (k and n) and Fick (Deff1) Models. In addition, mass transfer parameters (drying coefficient (S), lag factor (G), Biot number (Bi), effective diffusivity (Deff2), external mass transfer (hm)); and the activation energy were analysed. As results, the Page model showed the best fit, Deff1 and k parameters increased with temperature, especially for RW drying at 95 °C. RW method reduced the HA drying time by more than 30%. Furthermore, the 0<Bi<0.4 values were related to variations in internal resistance with temperature, except for HA drying at 95 °C, where the external resistance was also reduced. In conclusion, mass transfer parameters suggested that internal resistance was more important during HA drying, while RW was the most effective method since it needed lower time to dry samples.

Effect of blueberry addition on antioxidant activity, textural, microbiological and physicochemical properties of strained yoghurt.

In this research, the microbiological, physicochemical, rheological, textural, sensory properties and antioxidant activity of blueberry pulp added (0, 4%, 8% and 12%) strained yoghurt samples were investigated during a 28 day storage period. The Lactobacillus delbrueckii spp. bulgaricus and Streptococcus thermophilus counts in the samples were found to have decreased at the end of the storage period. The lightness, yellowness/blueness and whiteness index values showed a decrease depending on the addition of blueberry, while the redness/greenness values increased. The addition of blueberry had a negative the effects on the fat and protein values, while it had a positive effect on the total solids values. The storage period did not significantly change any of the physicochemical, colorimetric or rheological properties of the strained yoghurt samples. The general acceptability scores of the sample containing 12% blueberry were higher than the other samples. The antioxidant activities and total phenolic content of the strained yoghurt samples increased in accordance with blueberry concentration, while the firmness and work of the shear values decreased. In conclusion, it was determined that the addition of blueberry pulp at a 12% ratio could be used to enhance the nutritional and functional properties of strained yoghurts.

Production of blueberry pulp powder by microwave-assisted foam-mat drying: Effects of formulations of foaming agents on drying characteristics and physicochemical properties

Foaming agents influence the feasibility of microwave-assisted foam-mat drying (MFD) for the production of blueberry pulp powder (BPP). In this study, the effects of the foaming agents on the drying characteristics of foamed blueberry pulp (FBP) and physicochemical indicators of BPP were investigated by using the formulations containing egg white powder (EWP, 0, 4, 8 g/100 g), maltodextrin (MD, 0, 5, 10 g/100 g) and carboxymethylcellulose (CMC, 0, 0.5, 1 g/100 g). Results showed that the co-addition of EWP and MD obviously influenced the drying rate of FBP. The solubility and porosity of BPP increased significantly (P < 0.05) with increasing concentrations of EWP, MD and CMC. The physicochemical indicators of BPP were evaluated using the principal component analysis method because of the significant differences in color, browning index (BI) and total anthocyanin content (TAC) for BPP under different formulations of foaming agents. The optimal formulation consisted of EWP, MD and CMC with the ratio of 16:20:1 can achieve high drying rate and desired physicochemical quality with high solubility and porosity, relatively high TAC and BI. This study may provide guidance for the production of high physicochemical quality powder with high moisture content, heat sensitivity as well as high viscosity like blueberry pulp.

Drying characteristics and product quality of whole blueberry pulp in vacuum drying process

Abstract A pilot-scale vacuum dryer with visualization system was used to study the drying characteristics of the whole blueberry pulp. The heating temperature, operating pressure and initial material thickness had significant effects on the drying characteristics and the retentions of total monomeric anthocyanins and vitamin C in dried blueberry powder (P &lt; 0.05). According the heat transfer mode inside the material, the whole drying process could be divided into three periods: the boiling drying period, the convective drying period, and the conductive drying period. Most of water in the material was evaporated in the boiling and convective drying period. Considering the drying characteristics and dried product quality comprehensively, an optimal drying condition for whole blueberry pulp were: heating temperature 70 °C, operating pressure 1 kPa, and the initial material thickness 5 mm. It further compared the drying time, nutrients retention, hygroscopicity and microstructure of the product obtained by vacuum and vacuum freeze drying. The drying time of vacuum drying (1.2 h) was much shorter than that of vacuum freeze drying (44 h); the retentions of the total monomeric anthocyanins and vitamin C in dried blueberry powder of vacuum drying (67.9, 46.7%) were lower than that of vacuum freeze drying (79.0, 85.8%); while the hygroscopicity of vacuum dried powder was less than that of the freeze-dried product. The SEM images displayed that the surface of the vacuum-dried blueberry powder was porous, and the vacuum freeze-dried product was lamellar.

Development of Soy Milk Based Functional Fruit Yogurt Fortified with Extra Virgin Olive Oil

Cardiovascular diseases (CVD) and obesity are the most increasing world health challenge in recent days. To prevent these health problems, food researchers are intensively focusing to replace animal fat by healthy vegetable item with incorporation of different bioactive compounds. This study was conducted to develop a novel yogurt using different ratio of soy and cow milk. Blueberry pulp, extra virgin olive oil and stevia were used in the bottom portion to enhance functionality of the developed yogurt against CVD. All developed yogurt samples were analyzed for taste, texture and overall acceptability. Sensory analysis showed that, the yogurt developed from 75% soy milk and 25% cow milk had the highest overall acceptability.

Effects of blanching on extraction and stability of anthocyanins from blueberry peel

Blueberry is rich in anthocyanins, but accounting for 98.2% of the total anthocyanins are in blueberry peel and difficult to release, due to the barrier effect of the cell wall, and the oxidation of polyphenol oxidase also lead to anthocyanins loss. The blanching has a desired effect on the blueberry cell wall and polyphenol oxidase. Therefore, the influences of blanching were studied. The results indicated that the total anthocyanin content of the pulp from the whole blueberry blanching was 1.3 times higher than that of the crushed pulp blanching, and the anthocyanin content obtained from the steam blanching was 0.19 mg/100 g more than the boiling water; the maximum value of 125.35 mg/100 g was reached at 2 min of steam blanching, and the polyphenol oxidase activity was reduced to less than 10%, steam blanching showed a good effect on anthocyanins extraction. Based on the optimal blanching condition, the pulp from blanched blueberries was less red and more blue than the non-blanched, due to the more of malvidin-glycosides and the addition of delphinidin-glycosides and petunidin-glycosides; the retention rate remained at 82% and the degradation rate remained around 1.09 after 40 days. This study could be proposed to apply on the blueberry pulp production for improving the anthocyanins extraction rate and stability.

The analysis of cell wall degrading enzymes in ripening blueberry pulp in different post-harvest temperature

The ripening blueberry (in purple skin) were stored in refrigeration condition (4°C) and room temperature (25°C). By measuring the changes of PG, PME and β-Gal enzyme activities in blueberry over a period of time, we found that the changes in enzyme activities of PG and PME were negatively correlated with the softening of blueberry, and low temperature can inhibit the increase of PG and PME enzyme activity in the early stage.

ALTERNATIVES FOR PRESERVATION OF BIOACTIVE COMPOUNDS IN BLUEBERRY PULP: HEAT TREATMENT ASSOCIATED WITH THE ADDITION OF XANTHAN PRUNI

ABSTRACT In this study, to increase the preservation of phenolic bioactive compounds and antioxidant activity in blueberry pulp, heat treatment associated with addition of xanthan gum was used. A commercial mixture of blueberries (Powerblue, Climax and Bluegen cultivars) was added with 0.08% (w/w) citric acid and subjected to heat treatment by direct heating until 90 °C in conventional open pan (OP) and by direct application of steam (AS); both with and without the addition of xanthan pruni (OPX and ASX), followed by pulping. Samples of only frozed fruits were considered as control. The five treatments remained under freezing and were evaluated until 90 days of storage for antioxidant activity, phenols, flavonoids and total monomeric anthocyanins. The results show that, with the exception of phenolics, heat treatment with direct steam application and xanthan addition favored bioactive compounds preservation during storage. These factors influenced positively on the anthocyanins stability during frozen storage for 90 days. The xanthan addition favored antioxidant activity preservation; preservation for antioxidant activity by ABTS and DPPH, in all heat treatments, was observed.

Characterization and application of blueberry pulp (Vaccinium sp.) fresh and powder in frozen yogurt

The choice for a healthy diet that enhances quality of life has increased in recent years causing food manufacturers seek to meet consumer demand, differentiating products and services. Regular consumption of fermented foods like yogurt and frozen foods rich in antioxidants such as blueberries is recognized as beneficial to maintaining good health. This effect is attributed, in part, the lactic acid bacteria used in the preparation of frozen yogurt that has therapeutic properties and the presence of phenolic compounds present in blueberries, which counteract the effect of free radicals. Thus the aim of this study was to develop and characterize pulp added frozen yogurt blueberry and fresh powder. The yogurt made with frozens pulps were characterized and compared with a control formulation with added red dye Bordeaux. From the analyzes, it was concluded that the pulp of fresh blueberries showed levels of total phenolics and flavonoids in higher amounts in the pulp powder can be a viable alternative to coloring of in natura instead of artificial coloring.

ANTHOCYANIN AND ANTHOCYANIDIN CONTENT OF HIGHBUSH BLUEBERRIES CULTIVATED IN BRAZIL

The objective of this study was to apply a HPLC methodology for qualitative and quantitative analysis of the six anthocyanidins present in fruits and to analyze the anthocyanin and anthocyanidin content of blueberries cultivated in Southern Brazil. The samples used belong to highbush blueberries (Vaccinium corymbosum) cultivars. Total anthocyanin content was determined by the pH differential method and an HPLC gradient elution system with C18 column and UV-Vis detection at 520 nm were used for separation and quantification of the anthocyanidins. Total anthocyanin content was of 128 ± 3 mg per 100 g of fresh pulp. Blueberry pulp presented 55 % of delphinidin, 8 % of cyanidin, 3 % of peonidin and 34 % of malvidin. Pelargonidin was not identified in the sample and petunidin was below the limits of quantification. The results were similar to those reported in studies using North American and European blueberries.

Effects of ohmic and conventional heating on anthocyanin degradation during the processing of blueberry pulp

The present work evaluates the anthocyanin degradation in blueberry pulp after thermal treatment using ohmic and conventional heating. The ohmic heating technology was studied using a rotatable central composite design, and the variables studied were voltage and solids content. The anthocyanin content of the samples was determined using HPLC. The results show that degradation increased with both increasing voltage and increasing solids content. The comparison between ohmic and conventional heating showed that when lower voltage levels were used, the percentage of degradation was lower or similar to those obtained during conventional heating. However, for high electric fields, the pulp processed using ohmic heating exhibited higher anthocyanin degradation.

Effect of Blueberry on Spreadable Processed Cheese

Blueberry is a kind of wild berry with high nutrition values. It contains a great amount of anthocyanin, organic acid and fiber, which significantly affects sensory evaluation, pH value, texture profile analysis (TPA) and microstructure. This study determined the effect of blueberry pulp on spreadable processed cheese through examining pH value, TPA, microstructure and color-difference. The results showed that increased blueberry content lowered pH value, remarkably transformed microstructure and TPA (P<0.05). Overloaded fiber in blueberry ruined the network structure of casein gel, thus 10% of blueberry performed better, more than that additive volume, sensory evaluation was worsen and gel structure was spoiled gradually. The blueberry sample lowered L*, b* and slightly increased a*, resulting in blueberry samples presented light amethyst, while sterilizing samples presented dark pink because of the lost of anthocyanin.

Rheological behavior of blueberry ( Vaccinium ashei) purees containing xanthan gum and fructose as ingredients

In the present work the influence of temperature, xanthan gum and fructose addition on rheological behavior in steady state of blueberry puree was evaluated. The blueberry pulp was formulated with addition of xanthan gum (1.6, 2.0, 2.5, 3.0 and 3.3%) and fructose (6.6, 10.0, 15.0, 20.0 and 23.4%). Rheological data were obtained by shear rate scan tests in a rotational rheometer, with geometry of concentric cylinders in temperatures of 27, 40, 60, 80 and 93 °C. The thixotropy analysis was made through the calculation of the difference between the areas under up and down cycles’ flow curves. The analysis of the formulation influence on puree viscosity was carried out in two stages: i) selection of an appropriate rheological model for representation of data obtained in experiments and ii) statistical analysis of formulation and temperature influence on rheological parameters of selected model. Three 2-parameter models (Bingham, Ostwald–de Waele and Casson) and three 3-parameter models (Herschel–Bulkley, Mizrahi–Berk and Sisko) were tested. Based on the values of correlation coefficients and variance of the estimated parameters, Casson model was chosen for fitting of experimental data. The content of xanthan gum appears as a determinant variable of the rheological behavior of the puree, both at short and long times. The correlation among the variables studied was represented through statistical models which could be used for the development of formulations with specified viscosity in the range of additive concentrations studied.