Strawberry Juice Research Articles

Microencapsulation of strawberry juice in Agave angustifolia fructans: effect of spray‐drying conditions on the anthocyanin content and physicochemical properties

SummaryThe searching of alternative products that help reduce sugar consumption is a recurring objective due to the high number of overweight people in the world. The spray drying process of natural strawberry juice (SWJ) was evaluated using Agave angustifolia fructans as an encapsulating agent. Five fructan concentrations and three drying conditions were evaluated. The microcapsules obtained were characterised by anthocyanins content (UVvis), moisture percentage, hygroscopicity, colour, Tg, morphology (light scattering and SEM) and FTIR. Considering a recovery yield above 50%, the inlet/outlet temperatures of 180/90–95 °C and 15% of fructans were the conditions to obtain the powders with a hygroscopicity of 31%, anthocyanin retention of 84% and the highest Tg (54 °C). FTIR spectra and SEM evidenced that fructans can act as a homogeneous encapsulating matrix of SWJ. Therefore A. angustifolia fructans can be an alternative of low‐caloric power for the encapsulation of SWJ through spray.

Effect of Ultrasonic, Thermal and Enzymatic Treatment of Mash on Yield and Content of Bioactive Compounds in Strawberry Juice

Strawberries are rich in bioactive compounds that may be of health importance. The technological process often significantly reduces the content of such compounds in the product. The study aimed to compare the effect of enzymatic, ultrasonic and thermal mash treatment on the content of ascorbic acid, anthocyanins, phenolic compounds and the antioxidant activity of strawberry juice. In addition, the effect of increased temperature assisting ultrasonic mash treatment and the use of a vacuum for a short period to remove air from the mash during pectinolysis was investigated. A significant increase in the efficiency of juice pressing was obtained for enzymatic treatment (by 40%), thermal and thermosonication (16%). It was found that the applied methods yield different results depending on the tested compounds. In the case of anthocyanin, the most effective method was thermosonication, which contributed to a 40% increase in their content. The enzymatic and thermal methods resulted in a two-fold increase in the content of phenolic compounds. The antioxidant activity of the juice from the treated mash (regardless of the method used) was significantly higher than samples from the untreated mash. A significant correlation (r = 0.77) was noted between antioxidant capacity and non-anthocyanin phenolic compound content in the tested juices.

FUNCTIONAL FOODS OF PAKISTAN AND THEIR ROLE IN SENESCENCE

Functional foods can be used as a tool for healthy & longer life span. The term “functional food” is tossed to emphasize the role of nutritive substances in the prevention and eradication of chronic disease development. The aim of this study is to identify functional foods of Pakistan for their anti-aging potential. In this regard, the ethanolic extract or fresh juices of fifty functional foods, mostly advised by nutritionists, were assessed for their ability to inhibit glycation and oxidative stress. Our analysis showed that out of 50 functional foods, 44 of them have significantly reduced the formation of advanced glycation end products. The Pomegranate peel extract, Strawberry juice, coffee powder, and areca nut showed more than 90% AGEs inhibition at the concentration of 1 mg/ml. Furthermore, antioxidant potential of all these 50 functional foods was also assessed for antioxidant activity using DPPH assay. In this assay, the most pronounced effect (90% free radical scavenging activity) was observed with Cumin seeds extract, Purple Onion extract, Grapefruit juice and Oregano extract. In conclusion, the present study highlights several easily available dietary substances of Pakistan, whom consumption can help prevent age related disabilities and may contribute to healthier and longer life span.

Aroma in freshly squeezed strawberry juice during cold storage detected by E-nose, HS–SPME–GC–MS and GC-IMS

Aroma in freshly squeezed strawberry juice during cold storage detected by E-nose, HS–SPME–GC–MS and GC-IMS

Clarification of pomegranate and strawberry juices: Effects of various clarification agents on turbidity, anthocyanins, colour, phenolics and antioxidant activity

Effects of clarification on turbidity, anthocyanins (ACNs), colour, phenolics, ascorbic acid and antioxidant activity (AA) of pomegranate (PJ) and strawberry juices (SJ) were investigated. Cold-clarification was applied to PJ using only gelatine. For hot-clarification of both juices, bentonite, gelatine and kieselsol were used. Moreover, pectolytic enzyme was added to SJ that contains pectin. Depectinization caused an increase in colour density of SJ and bentonite treatment resulted in low turbidity (9.5 NTU). However, gelatine and kieselsol significantly reduced ACN content (15%) and increased turbidity (70.1 NTU). In PJ, no step during hot-clarification provided low turbidity (93.2–162.0 NTU), while relatively low turbidity (28.7 NTU) and anthocyanin loss (9.8%) was achieved during cold-clarification. Hot-clarification of SJ showed no effect on AA and phenolics, while cold-clarification of PJ reduced both to a limited extent. Therefore, depectinization and bentonite treatment are recommended for hot-clarification of SJ and gelatine for cold-clarification of PJ.

Multi-frequency power thermosonication treatments of clear strawberry juice: Impact on color, bioactive compounds, flavor volatiles, microbial and polyphenol oxidase inactivation

Strawberry juice is popular among consumers for its bright color, unique flavor and rich nutrition. The aim of this study was to explore the suitable multi-frequency power thermosonication (TS) treatments to meet the requirements of microbiological safety for strawberry juice while maximizing the preservation of its quality properties. The TS treatments included 60 °C /5 min and 55 °C /15 min under dual-frequency concentrated ultrasound (DCU) and 60 °C /15 min and 55 °C /20 min under sweep-frequency divergent ultrasound (SDU). The results showed that all treatments could meet the requirements of commercial sterility (at 90 °C for 1 min). Compared with thermal processing (TP) at 90 °C for 1 min, TS treatment significantly improved the color properties of strawberry juice. SDU-60 °C and SDU-55 °C greatly retained the active ingredients in the strawberry juice. TS treatments had a stronger ability to maintain the aroma compared to TP. Especially, SDU-60 °C was the best treatment at retaining quality properties of strawberry juice with the highest comprehensive sensory evaluation score (7.68). Therefore, the results can provide scientific basis for industrial production of strawberry juice. Industrial relevanceIn the current study, results showed that TS maximized the overall quality of strawberry juice while achieving the effect of sterilization and enzyme inactivation. Among them, SDU-60 °C was the best treatment method to maintain the quality characteristics of strawberry juice, which can effectively reduce the loss of approximately 70% of total phenolic content. Thus, it provides the theoretical basis and technical support for the industrial production of strawberry juice.

Potency of Acid Content in Local and Imported Strawberry Fruit Extract (Fragaria X Ananassa) as Natural Ingredients for Teeth Whitening

Background: Bleaching treatment is a whitening treatment for discolored teeth to restore their aesthetic function. The bleaching agent that is commonly used is 35% carbamide peroxide. Strawberries contain malic acid which can whiten teeth. Purpose: This study aims to find out acid potential on strawberries as a natural ingredient for teeth whitening. Methods: 48 post-extraction permanent single-rooted teeth that had been coated with clear nail polish were soaked in black coffee for 2 days, then 16 teeth were immersed in a local strawberry extract solution, 16 teeth were immersed in an imported strawberry extract solution and the other 16 teeth were immersed in a 35% carbamide peroxide gel solution and then observed and measured the color of the teeth after immersion at 24 hours and 48 hours. Results: There is potential for local and imported strawberry fruit extract in whitening teeth but the whitening potential when compared to carbamide peroxide is not significant (p>0.05). The whitening potential of imported strawberry juice is higher than that of local strawberry juice based on the average value. Conclusion: Based on research results, local and imported strawberry juice extracts have the potential to whiten discolored teeth.

Bacterial Evaluation of Fresh Juices Sold in Cafes and Restaurants in the City of Benghazi, Libya

Food safety is a big challenge that concern all human communities and food production factories. The information on the bacterial evaluations of fresh natural juices in the city of Benghazi remained very limited and unclear. This study was carried out to evaluate the bacterial contamination for two of the most popular selling freshly made juices, including mango and strawberry juices. The results of screening showed bacterial growth in 117 (91.41%) out of the total samples 128. The evaluation during the second season showed a higher bacterial growth rate of 96.55 %. The most predominant bacteria contaminating the targeted juices was Klebsiella pneumoniae, with an average of (36.21%), followed by fecal Escherichia coli (31.03%) for both juices. All the contaminated juices represented bacteria count out of the accepted value. Gram-negative pathogens showed resistance to limited antibiotics, including Amoxicillin, Amikacin, and Clarithromycin, whereas the Gram-positive bacteria showed higher resistance rates. This study concluded that, increase in bacterial diversity and bacterial count out of the accepted standard as well as the presence of fecal E. coli indicating a poor level of hygiene during the process of preparing juices, leading to the possibility of causing diseases and exposing people to food poisoning.

A Chemometric Investigation on the Functional Potential in High Power Ultrasound (HPU) Processed Strawberry Juice Made from Fruits Harvested at two Stages of Ripeness.

This work aimed to investigate the influence of high-power ultrasound (HPU) technology on the stability of bioactive compounds in strawberry juices obtained from fruits with different stages of ripeness (75% vs. 100%) and stored at 4 °C for 7 days. HPU parameters were amplitude (25, 50, 75, and 100%), pulses (50 vs. 100%) and treatment time (5 vs. 10 min). Amplitude and pulse had a significant effect (p ≤ 0.05) on all bioactive compounds except flavonols and hydroxycinnamic acids. The treatment duration of 5 min vs. 10 min had a significant positive impact on the content of anthocyanins, flavonols and condensed tannins, while the opposite was observed for total phenols, whereas no statistically significant effect was observed for hydroxycinnamic acids. The temperature changes during HPU treatment correlated positively with almost all HPU treatment parameters (amplitude, pulse, energy, power, frequency). Optimal parameters of HPU were obtained for temperature changes, where the highest content of a particular group of bioactive compounds was obtained. Results showed that by combining fruits with a certain ripeness and optimal HPU treatment, it would be possible to produce juices with highly preserved bioactive compounds, while HPU technology has prospects for application in functional food products.

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 3months 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.

Strawberry preservation using combination of yam bean starch, agarwood Aetoxylon bouya essential oil, and calcium propionate edible coating during cold storage evaluated by TOPSIS-Shannon entropy

The effect of edible coatings made from yam bean starch (ST), agarwood bouya essential oil (ES), and calcium propionate (CP) on strawberry fruit in cold storage for 16 days was investigated. Strawberries coated with four different coating formulations and uncoated fruits were packed in sealed containers and stored at 4 °C with 85 % of humidity. Antifungal evaluation was conducted on the coating solution (membrane permeability and germination of Botrytis cinerea) and edible film (microstructure analyzed using atomic force microscopy), as well as testing at 4-day intervals on fresh fruit (weight loss, surface color, firmness, microstructure using scanning electron microscopy, and antifungal activity) and physicochemical analysis of strawberry juice (total soluble solid, citric acid, ascorbic acid, pH, and titratable acidity). Each result was then tested using TOPSIS-Shannon entropy analysis. From these tests, the edible coating treatment with ST-ES was the best treatment in this study (has Ci 0.839 as the highest of all untreated and treated sample) and better than fruit without coating, demonstrating that the coating was able to maintain the quality of strawberries during storage. At the final day of storage ST-ES samples has L* 30.9, a* 26.65, b* 16.36, total soluble solid 3.98 Brix/%.

Improvement in color expression and antioxidant activity of strawberry juice fermented with lactic acid bacteria: A phenolic-based research

The aim of this study was to investigate the impact of lactic acid bacteria fermentation on color expression and antioxidant activity of strawberry juice from the perspective of phenolic components. The results showed that both Lactobacillus plantarum and Lactobacillus acidophilus were able to grow in strawberry juice, promote the consumption of rutin, (+)-catechin and pelargonidin-3-O-glucoside, and increase the content of gallic acid, protocatechuic acid, caffeic acid and p-coumaric acid compared to group control. Lower pH environment in fermented juice was likely to enhance the color performance of anthocyanins and increase its parameters a* and b*, making the juice appear orange color. In addition, the scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant capacity (FRAP) were improved and closely related to polyphenolic substances and strain’s metabolites in fermented juice.

Postharvest Eucalyptus Leaf Extract Application Extends the Sustainable Supply of Strawberries by Retaining Physicochemical Quality during Cold Storage

Strawberry is a delicate fruit with a short shelf life after harvest. High metabolic activities and fungal decay deteriorate its quality. In an attempt to extend its shelf life and maintain its quality while retaining its antioxidant potential, the harvested fruits of strawberry cv. Chandler were dipped in 30% eucalyptus leaf extract (ELE). Weight loss, fungal decay index, percentage of decayed fruits, respiration rate, and electrolyte leakage were all reduced in ELE-treated strawberries. The enzymatic activities of catalase in fruits increased initially until the fifth day of storage but then started to decline during the later period while superoxide dismutase and peroxidase activities continued to rise until the 10th day and then declined. With higher contents of total phenolics, ascorbic acid, total antioxidants, and anthocyanin, the application of ELE maintained the general acceptance, firmness, flavor, and marketable fruit percentage. Titrable acidity (TA) and sugar–acid ratio (SAR) were also significantly affected by ELE application. A declining trend was observed in TA during storage, along with an increase in SAR. The pH and soluble solid contents of strawberry juice were not significantly changed by the application of ELE; however, both attribute scores were greater than those for the control. In conclusion, ELE could be used as an environmentally safe method to postpone senescence and maintain postharvest quality for up to 15 days.

In situ electrodeposition of Cu-BDC metal-organic framework on pencil graphite substrate for solid-phase microextraction of some pesticides.

The study focuses on the electrochemical deposition of copper benzene-1,4-dicarboxylate framework (Cu-BDC MOF) on the surface of a very cheap pencil graphite (PG) substrate for utilization as the sorbent in fiber solid-phase microextraction (SPME) of two chosen pesticides, including abamectin and amitraz for the first time. The extracted pesticides were quantified by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). The UV detector was set at 236nm wavelength. Based on the optimized condition, the presented technique showed a good linear range (2-500µg L-1 and 2-100µg L-1), suitable limits of detections (LODs = 0.60 and 0.5µg L-1), satisfactory enhancement factors (EFs = 128 and 105), good absolute recoveries (ARs% = 64% and 53%) and spiking recoveries in the range 87.4-110.0% for amitraz and abamectin, respectively. Intra- and inter-day relative standard deviations were found within the range 1.2-3.8% and 0.6-1.9%, respectively. The method was successfully employed for the quantification of the selected pesticides in strawberry juice, lemon juice, orange juice, tomato juice, and honey.

Growth Prediction of the Total Bacterial Count in Freshly Squeezed Strawberry Juice during Cold Storage Using Electronic Nose and Electronic Tongue.

The growth models of total bacterial count in freshly squeezed strawberry juice were established by gas and taste sensors in this paper. By selecting the optimal sensors and fusing the response values, the Modified Gompertz, Logistic, Huang and Baranyi models were used to predict and simulate the growth of bacteria. The results showed that the R2 values for fitting the growth model of total bacterial count of the sensor S7 (an electronic nose sensor), of sweetness and of the principal components scores were 0.890-0.944, 0.861-0.885 and 0.954-0.964, respectively. The correlation coefficients, or R-values, between models fitted by the response values and total bacterial count ranged from 0.815 to 0.999. A single system of electronic nose (E-nose) or electronic tongue (E-tongue) sensors could be used to predict the total bacterial count in freshly squeezed strawberry juice during cold storage, while the higher rate was gained by the combination of these two systems. The fusion of E-nose and E-tongue had the best fitting-precision in predicting the total bacterial count in freshly squeezed strawberry juice during cold storage. This study proved that it was feasible to predict the growth of bacteria in freshly squeezed strawberry juice using E-nose and E-tongue sensors.

Effect of Antioxidant-Rich Moringa Leaves on Quality and Functional Properties of Strawberry Juice.

Moringa oleifera and strawberry are cultivated extensively worldwide and are divinely blessed with an enormous amount of nutritional and medicinal constituents, such as vitamin C, vitamin E, iron, potassium, and phenolic antioxidants that play a pivotal role in treating, confining, and preventing diabetes and many kinds of cancer. The focus of the study is to develop different samples of highly acceptable ready to serve (RTS) Moringa strawberry juice blend by underutilizing Moringa and strawberry juice in different proportions. Moringa oleifera's bitter taste and green color steeply limits its acceptability and counter this drawback utilized with strawberry juice. The physicochemical analysis of blended juice was performed to investigate the suitability and keeping quality of the juice mixture. The collected data signify that pH titratable acidity (TA) and total soluble solids (TSS) the slight modification after the inclusion of Moringa juice extract and throughout the storage. The Moringa treatment positively improved the total phenolic content (TPC), antioxidant, and vitamin C from 12 to 49.17 mg GAE/100g, 61.41 to 87.69%, and 64.03 to 86.65 mg/100 mL, respectively, but there was a slight decline in antioxidant quantity while stored under refrigerated conditions for one month. An assimilative trend was noticed in TPC and vitamin C, which collapsed from 49.17–36.32 mg GAE to 86.65–79.19 mg, respectively. In accordance with sensory analysis T2 (90% strawberry juice and 10% Moringa extract), the juice blend was rated best in context to flavor, color, and taste. This juice blend proved to be greatly effective especially for children suffering from malnutrition as well as women to counter with its appreciable number of nutritional constituents.

Multi-Objective Optimization of Beverage Based on Lactic Fermentation of Goat’s Milk Whey and Fruit Juice Mixes by Kefir Granules

Numerous fruits are produced in Ecuador, of which about 40% are never eaten. In addition, fresh goat cheeses are in high demand. However, goat cheese generates goat milk whey with high contamination loads, and, therefore, it must be adequately treated before being discharged into ecosystems. This research aims to use a mixture of tree tomato, common strawberry juices, and goat’s milk whey, to be statically fermented by milk and water kefir grains (WKG) for 48 h. For this, a dual mixture design of L-optimal response surface methodology was carried out to find the conditions that maximized all the responses evaluated (lactic-acid bacteria and yeasts concentrations and the overall acceptability assessed on a 7-point scale). Experiments were carried out in San Gabriel, Ecuador. Temperatures during the day and night were 20.2 ± 0.3 °C and 18.7 ± 0.3 °C, respectively. Three conditions were selected, where the highest response values were reached. Complementary experiments demonstrated the validity of the models. When comparing the results of the present study with similar ones carried out previously, higher values were observed in the concentration of yeasts, which seems related to the presence of the WKG. It is concluded that they could be suitable functional beverage candidates.

Effect of Multi-Mode Thermosonication on the Microbial Inhibition and Quality Retention of Strawberry Clear Juice during Storage at Varied Temperatures.

Strawberry juice, which is rich in nutrients and charming flavor, is favored by consumers. To explore whether multi-mode thermosonication (MTS) can ensure the quality stability of strawberry clear juice (SCJ) during storage, the effects of microbial inhibition, enzyme activity, and physicochemical properties of SCJ pretreated by MTS were evaluated during storage at 4, 25, and 37 °C in comparison with thermal pretreatment (TP) at 90 °C for 1 min. The MTS, including dual-frequency energy-gathered ultrasound pretreatment (DEUP) and flat sweep-frequency dispersive ultrasound pretreatment (FSDUP), were conducted at 60 °C for 5 and 15 min, respectively. Results showed that the total phenols, flavonoids, anthocyanins, ascorbic acid, and DPPH free radical scavenging ability of SCJ decreased during the storage period. The control sample of SCJ was able to sage for only 7 days at 4 °C based on the microbiological quality, while the FSDUP and DEUP group extended the storage period up to 21 and 14 days, respectively. The polyphenol oxidase in SCJ pretreated by MTS did not reactivate during the storage period. The MTS remarkably (p < 0.05) reduced the color deterioration, browning degree, and nutrient degradation during the storage period. Moreover, the FSDUP group exhibited the maximum shelf life with a minimum loss of quality, demonstrating that it was the most suitable processing method for obtaining high-quality SCJ. It can be concluded that the MTS has the potential to inhibit enzymatic browning, inactivating microorganisms, preserve original quality attributes, and prolong the shelf life of SCJ.

Characterization and Classification of Direct and Commercial Strawberry Beverages Using Absorbance-Transmission and Fluorescence Excitation-Emission Matrix Technique.

The subject of this study was to characterize the absorption and fluorescence spectra of various types of strawberry beverages and to test the possibility of distinguishing between direct juices and pasteurized commercial products on the basis of their spectral properties. An absorbance and transmission excitation–emission matrix (A-TEEMTM) technique was used for the acquisition of spectra. The obtained spectra were analyzed using chemometric methods. The principal component analysis (PCA) revealed differences in both the absorption spectra and excitation–emission matrices (EEMs) of two groups of juices. The parallel factor analysis (PARAFAC) enabled the extraction and characterization of excitation and emission profiles and the relative contribution of four fluorescent components of juices, which were related to various groups of polyphenols and nonenzymatic browning products. Partial least squares–discriminant analysis (PLS-DA) models enabled 100% correct class assignment using the absorption spectra in the visible region, unfolded EEMs, and set of emission spectra with excitation at wavelengths of 275, 305, and 365 nm. The analysis of variable importance in projection (VIP) suggested that the polyphenols and nonenzymatic browning products may contribute significantly to the differentiation of commercial and direct juices. The results of the research may contribute to the development of fast methods to test the quality and authenticity of direct and processed strawberry juices.

The Application and Optimization of HIPEF Technology in the Processing of Juice from Strawberries Harvested at Two Stages of Ripeness.

The aim of this study was to investigate the influence of high intensity pulsed electric field (HIPEF) technology on the stability of total phenols, anthocyanins, hydroxycinnamic acids, flavonols, and condensed tannins in strawberry juices (Fragaria x ananassa Duch. cv. ‘Albion’) with different ripening stages (75% and 100%) and stored at +4 °C for 7 days. The HIPEF parameters studied were: (i) electric field strength (40 and 50 kV cm−1), (ii) frequency (100 and 200 Hz), and (iii) treatment duration (3 and 6 min). Of the HIPEF parameters studied, electric field strength and frequency had a statistically significant effect on the content of all phenolic compounds. Treatment duration showed no statistically significant effects on phenolic compounds except for flavonols and condensed tannins. Storage had a positive effect on the stability of most of the phenolic compounds, with the exception of flavonols. Optimization of HIPEF processing showed that strawberry samples at both ripeness levels were suitable for HIPEF treatment to obtain functional fruit juices with a high content of polyphenols.