Vol. 19 No. 6 (2021)

Probiotic beverage products derived from plants are increasingly interested in research. Guava is a fruit with high fiber, vitamin C content and contains many active antioxidants that are good for health. Lactobacillus plantarumis a safe lactic acid bacterium, widely used in food fermentation. This study aimed to evaluate probiotic potential of Lactobacillus plantarumstrains. By measuring OD620nm, applying the agar punching method on the medium with the corresponding substrate supplementation, the diffusion on agar plates method. L. plantarumDH 7.12 was determined with good probiotic properties such as low stomach pH tolerance, bile salt tolerance, generate all 3 extracellular enzymes (amylase, protease, cellulase), antagonist to pathogensEcoliand Salmonella. When L. plantarumDH 7.12 was added into guava juice with cell concentration 108 CFU/ml. The product was assured of organoleptic quality and the remaining amount of probiotic bacteria reached 107 CFU/ml after 28 days of storage at a temperature 5 ± 1C

Docynia indicais a fruit with high pharmacological potential because it contains many antioxidants such as phenolics and flavonoids. This study aims to optimize conditions for extracting phenolic and flavonoid compounds from this fruit through microwave-assisted. The effects of the various parameters including solvent concentration, solvent/material ratio, microwave power, extraction time on collection capability of bioactive compounds were studied individually. The extraction condition was optimized by Response Surface Methodology (RSM). The results showed that the optimal condition for extracting bioactive substances from lyophilized Docynia indica was 40alcohol solvent, the ratio of solvent/material was 33.37/1, microwave power was 627.64W (However, in fact, this power cannot be adjusted, so the authors used the closest power of 630W), the extraction time is 3.02m. With the above indicated conditions, the total polyphenol and flavonoid contents were obtained 42.28 ± 0.39mg GAE/g CK and 15.47 ± 0.38mg CAE/g CK, respectively.

The study aimed to investigate the effects of temperature and germination time on the changing of gamma-aminobutyric acid (GABA), phytic acid and the hyacinth bean’s compositions (total solid content, protein, lipid, ash content). The seeds of Hyacinth bean were germinated at 26, 28, 30 and 32C for 12, 24, 36 and 48h. GABA and phytic acid were analyzed using the colorimetric methods. Total solid, protein, lipid and ash content were analyzed using the drying method, Kjeldahl, Soxhlet and incineration, respectively. The results showed that the germination was significantly influenced by GABA, phytic acid and chemical compositions of the germinated hyacinth bean seeds. Hyacinth bean seeds were germinated at 30C for 36h showed the highest content of GABA and protein. Phytic acid and total ash content significantly decreased as prolonging germination without being affected by incubated temperature. Lipid and total solid content also decreased as increasing germination temperature and prolonging incubation time.

This study was conducted to select, identify lactic acid bacteria strain producing enzyme -galactosidase with trans-galactosylation activity and determine the characteristics of enzyme applied in Galacto-oligosacchride (GOS) production. -galactosidase of lactic bacterial strain FV4 isolated from the fermented mustardhas been recorded as trans-galactosylation enzyme which converts lactose to GOS via the conversion product by using thin-layer chromatography (TLC).FV4 strain was identified and named Lactobacillus fermentum FV4 based on the comparison of sequence encoding for 16rRNA gene. Characterization of technical –galactosidase from this strain indicated that enzyme activity was the highest in the pH ranged from 6.5 to 8.5 and the most stable was at pH 7.5, after 24h of incubation in pH 7.5, the enzyme activity has still remained 92.8%. The optimal temperature of enzyme was 50Cand enzyme was very stable at 30Cin 24h of incubation. In addition, K+, Na+, DTT 1mM, 10mM, and Mg2+1mM activated the enzyme activity. Products of lactose conversion by using enzyme β-galactosidasewere analyzed based on TLC and HPLC showed that 65% lactose was converted to 8% GOS within 6h.

Mandarin (Citrus reticulata)belongs to the citrus fruit family, has a high risk of damage due to contamination on fruit shells, the peel is crispy and easy to crush. This study aimed to identify the suitable postharvest treatment to prolong storage shelf-lifeof Bac Kan mandarin. The mandarin fruits were treated with 4 treatments: (i) distilled water washing (control); (ii) fruit treated with lime 1% on the stem; (iii) fruit washed with ozone solution on the skin; (iv) fruit dipped in ethanol 70% on the skin. The results showed that the treatment mode on ozone and ethanol gave higher quality mandarin when compared to other treatments. Especially, the ozone treatment gave the most effective in prolonging shelf-life of ‘Bac Kan’ mandarin, reach 33 days storage in low temperature (6±1C) and LDPE film packaging with the decay rate of the fruit is very low (4,2%).

Bitter melon seeds are rich in α-eleostearic acid (C18:3 9c11t13t). α-eleostearic acid with its conjugated double bonds may provide many potential health benefits, including anti-oxidant, anti-inflammatory, anti-tumor, anti-obesity and anti-diabetic effects. This study aimed to characterize bitter melon seeds of Prền pà tăng variety in Vietnam and to investigate the physicochemical properties of bitter melon seed oil extracted with ethyl acetate. The bitter melon seed oil extraction was optimized by using the response surface methodology. The results showed that the bitter melon seeds accounted for 3.93% of fruit weight, the seed with a high percentage of hull at 36.56%, the oil in seed kernel was 46.56%. The optimum extract condition of seed oil was ethyl acetate with solid/solvent ratio: 1/10, at 52C for 30 min. The experimental results properly conformed to the constructed model (R2 = 0.82). The bitter melon oil had the peroxide and free fatty acid index of 0.85 meq O2/kg oil and 2.93mg KOH/g oil, respectively. Vicine content in oil was 8.82 µg/g oil, which is safe forfood, pharmaceutical and cosmetic applications.

The study investigated suitable packaging materials for strawberry storage with Hyokan technology. Strawberries were harvested at 80% full-ripen when the fruit skin changed to red and stored using Hyokan technology at -2C, electric pressure 3.500V. Four packaging materials were investigated, including PE foam, PE clings film, filter paper and plastic box. The control sample was kept at 2-4C in a regular refrigerator. The control sample showed a significant decrease in sensory quality, nutritional quality and microorganisms. The fruit covered by PE cling film (CT5) had the best nutritional quality and sensory score, and microorganism. By using the Hyokan technology and PE cling film, after 21 days storage, the weight loss was 0.31%, waste 13.89%, TSS 7.83Bx, total axit1.15% and vitamin C 13.38 mg/g; the sensory score was a distinction; the total aerobic microorganism was within the standard 46/2007 QĐ-BYT.

The study investigated suitable packaging materials for strawberry storage with Hyokan technology. Strawberries were harvested at 80% full-ripen when the fruit skin changed to red and stored using Hyokan technology at -2C, electric pressure 3.500V. Four packaging materials were investigated, including PE foam, PE clings film, filter paper and plastic box. The control sample was kept at 2-4C in a regular refrigerator. The control sample showed a significant decrease in sensory quality, nutritional quality and microorganisms. The fruit covered by PE cling film (CT5) had the best nutritional quality and sensory score, and microorganism. By using the Hyokan technology and PE cling film, after 21 days storage, the weight loss was 0.31%, waste 13.89%, TSS 7.83Bx, total axit1.15% and vitamin C 13.38 mg/g; the sensory score was a distinction; the total aerobic microorganism was within the standard 46/2007 QĐ-BYT.

Tea (Camellia sinensisO. Kuntze) is one of the most popular crops and is considered a traditional beverage in many countries. The tea seed oil has been studied with the objectives to analyze the physical and chemical properties with a view for quality assessment, composition and applications. Physical and chemical properties such as state, specific gravity, acid value, peroxide value, iodine value, saponification value etc.were studied.Similar to olive oil, tea seed oil is a high-quality cooking oil with great stability because it has a large number of natural antioxidants including carotenoid (3.2 mg/kg), total polyphenols (8.68 mg/kg) and vitamin E (262.4 mg/kg). Moreover, tea seed oil is vegetable oil with high nutritional values due to its high content of unsaturated fatty acids (81.8 %), especially linoleic acid (22.3 %), which was previously proved to be useful in reducing cholesterol levels in the blood and preventing heart diseases, high blood pressure, and cancer. Studies show that different extraction methods of tea seed oil such as pressing, extracting by solvent, supercritical fluid, etc., yield oil with different efficiency and quality.

Passion fruitpeel accounts for a very high percentageof the total fruit weight. Therefore, taking advantage of this by-product source to extract pectin will both create valuable products for application in the food industry and contribute to solving environmental problems. This study aimed to find the optimal conditions for extracting pectin from the peelsof purple passion fruit and to evaluate the effect of extraction conditions on the degree of esterification of pectin. Using a central composite design (CCD) with a response surface methodology (RSM), the results showedthat the generated quadratic model adequately explained the data variation and significantly represented the actual relationship between the independent variables and the responses. This study also found the optimal conditions to extract pectin from passion fruit peelsas follows: citric axit concentration of 8.00%, temperature of 82.14C and extraction time of 81.07 min for the highest yield of pectin (24.42%). Thepectin extracted under the optimum conditions had the followingphysicochemical properties: equivalent weight (EW) of 586.92± 17.55; degree of esterification (DE) of 38.76± 1.52 %; methoxyl index (MI) of 3.94± 0.13 %; total anhydrouronic acid content (AUA) of 76.58± 1.19 %. Thesecharacteristics are suitable for the purpose of edible film making, opening up a potential application for this pectin. In addition, the extraction conditions had a marked effect on the degree of esterification of pectin from purple passion fruit peel.

This study was to evaluate the effects of growing seasons on the quality of tomato cv. Savior. The quality parameters of the tomato during fruit development, climacteric ripening and postharvest storage were analyzed using the instrumental methods. The results showed that the fruit weight of summer tomato (off-season tomato) was significantly smaller than that of winter tomato (on-season tomato) during fruit development and climacteric ripening. Meanwhile, total acidity of summer tomato was 1.5 times higher than that of winter tomato. Both summer and winter tomato shared a similar changing pattern in color, firmness and total soluble solid content. They showed the climacteric peak at the ripening stage 3 (turning color stage), which was 1.220 mmol CO2/kg.h for summer tomato and 1.331 mmol CO2/kg.h for winter fruit. This study has affirmed that tomato cv. Savior has a good heat tolerance capability, thus suitable to grow in both summer and winter seasons without clear differences in phenotype. Data in this study provide a background for further performing in-depth studies at the genomic and proteomic levels to discover the ripening mechanisms between tomato cv. Savior grown in winter and in summer.

The research aimedto identify the concentration effects of propionic acid (AP) combined with a membrane coated with a mixture of beeswax and carnauba wax (MW) at a concentration of 8% on quality and storage time of postharvest purple passion fruit. After being washed and left to dry, the fruits were dipped in AP solution0.25; 0.35; and 0.45% for 10 minutes.After being left to dry again, the fruits were coated with 8% MW. After continuing to be left to dry, the fruits were placed in a foam tray put in carton boxes and stored at 5 ± 1°C, RH = 85 ± 2%. The untreated fruits and uncoated fruits were used as controls. The respiration rate, the percentage of weight loss, the total soluble solids (TSS) content, the total titrable acidity(TTA) and vitamin C content, the total microorganism population on the surface of the fruits and the percentage of fruits decay were analyzed and evaluated throughout the storage period. Research results showed that AP at a concentration of 0.45% combined with8% MW coating (CT3) is the best treatment for reducing the respiration rate, the total microorganism population on the surface of the fruits, the percentage of fruits decay and weight loss, slowly reduced TSS, TTA and vitamin C content. After 42 days in storage purple passion fruit treated by CT3 had the percentage of general loss including weight loss and decay is 11.9% in comparison with the control sample had the percentage of general loss is 96.2%.

It has been demonstrated that roots ofMyxopyrum smilacifolium(Wall.) contain many bioactive compounds including polysaccharides, saponin, flavonoids. This study aimed to determine the effects of the single-factor model on the amount of polysaccharide extracted from roots of Myxopyrum smilacifolium(Wall.) Blume), as a basis on a fractional factorial design at three levels through the Box–Behnken experimental design. Extracts obtained from optimized conditions were used for evaluation of their antibacterial, antioxidant, and anti-inflammatory ability. The results of the single-factor showed that the time of using ultrasound, the ethanol concentration, solvent/ material ratio, and extraction temperature were 60 seconds at 37 kHz, 80%, 15/1 (ml/g), and 80C for 90 min respectively. Under the optimized conditions by using the Box–Behnken experimental design, the results showed that the time of using ultrasound, the ethanol concentration, solvent/ material ratio, and extraction temperature were 64.67 seconds at 37 kHz, 81.56%, 15.33/1 (ml/g), and80C for 90 min respectively; and the total polysaccharide content was 16.1948 mg/g of the root. The extracts of total polysaccharides were able to inhibit Staphylococcus aureusK, Staphylococcus aureus, Shigella flexneri, Bacillus subtilis, Escherichia coli, Pseudomonas spp with antibacterial ring diameters as follow: 8.01; 18.06; 8.03; 6.84; 15.33; 9.39, and 10.13 mmrespectively. There was an IC50value of 168.94 ± 5.28 (µg/ml) when evaluating antioxidant activity. The anti-inflammatory ability was 28.31 ± 1.04; 33.76 ± 1.06; 50.04 ± 2.03 and 71.14 ± 2.81 (% BSA denaturation) corresponds to the extract concentration of 0.78125; 1.5625; 3.125 and 6.350 (μg/ml) respectively.