Red pitaya juice (RPJ) was subjected to UV-C irradiation and the potential of UV as a pasteurization tool for reducing microbial load in pitaya juice was evaluated. Effectiveness of the hurdle concept, i.e. addition of citric acid (CA) and dimethyl dicarbonate (DMDC) was also studied. Total plate counts (TPC) and yeast and mould counts (YMC) achieved 2.43 log₁₀ and 2.7 log₁₀ reductions respectively after exposure to UV irradiation. Addition of the CA (0.5 - 2.0%) and dimethyl dicarbonate (DMDC) (5 - 20 µL/100mL) to pitaya juice reduced the microbial loads, with 1.5% CA and 15 µL/100mL DMDC being the most effective concentrations. Addition of CA and DMDC into RPJ prior to UV treatment achieved significantly higher microbial reduction compared to UV alone, which were 4.12 log ₁₀ and 4.14 log₁₀ reductions for TPC and for YMC, respectively.
Sonication is recognized as a potential food processing method to improve the functional properties of fruit juice. This study evaluated the effects of different sonication durations (20, 40, and 60 min) and thermal pasteurization on the nutritional, antioxidant, and microbial properties of noni juice. Fresh noni juice served as the control. The main organic acids detected were malic (57.54−89.31 mg/100 mL) and ascorbic (17.15−31.55 mg/100 mL) acids. Compared with the fresh sample, the concentrations of these compounds were significantly improved (p < 0.05) in the 60 min sonicated sample but reduced (p < 0.05) in the pasteurized sample. Moreover, sonication for 60 min resulted in increments of scopoletin, rutin, and vanillic acid compared to the fresh sample. The antioxidant activity of the juice sample was improved in the sample sonicated for 60 min. Irrespective of juice processing method, the level of microbial counts in noni juice was within the satisfactory level over the 8 weeks of refrigerated (4 °C) storage. This study highlights the feasibility of using ultrasound processing to enhance the quality of noni juice on the industrial scale.
Lime juice is in high demand due to a sour taste. Commercial thermal pasteurization extends juice shelf-life; however, fruit juice subjected to thermal pasteurization tends to change color and lose vitamin content. Lime juice was irradiated with ultraviolet-C (UVC) at dosages of 22.76, 30.19, and 44.24 mJ/cm2 to investigate effects on the physicochemical properties of lime juice. pH values of lime juice did not change while total soluble solids, turbidity, titratable acidity, sweetness, and color values of lime juice did change after UV treatments. Changes in quality index indicators were prominent at the highest UV dosage of 44.24 mJ/cm2. A low UVC dosage was effective for treatment of lime juice with minimal changes in juice properties.
This study was done to determine the effect of pasteurization on the stability of lactic acid bacteria (LAB) and its enzyme in raw and pasteurized cow’s and goat’s milk. The total viable count for plate count of the bacterial growth concentration was higher in both pasteurized cow’s and goat’s milk at 2.48 log CFU/ml. This is followed by raw cow’s milk (1.59 log CFU/ml) and raw goat’s milk (0.65 log CFU/ml). Lactic acid bacteria (LAB) was found to be similar in both raw cow’s and goat’s milk (p>0.05), and pasteurized milk of both animals also contained the same amount of LAB (p>0.05). LAB was still detected in pasteurized milk (p
The effect of storage time on the quality of ultraviolet-irradiated and thermally pasteurised pineapple juice was evaluated. The juices were irradiated with ultraviolet light (UV-C) at wavelength 254 nm (53.42 mJ/cm2, 4.918 s), thermally pasteurised at 800C for 10 minutes and stored at 40C for 13 weeks. There were significant changes in the total soluble solids, pH, titratable acidity and turbidity of UV-irradiated juice during storage, whereas for the same quality attributes of thermally pasteurised juice remained stable throughout the storage time. There were no significant changes in total phenolics for both treatments throughout the storage period. Other quality parameters (ascorbic acid, colour L, hue angle and chroma) were significantly affected by the storage time. Regarding the microbiological analysis, the total plate counts and yeast and mould counts of the UV-irradiated juice increased gradually throughout the 13 weeks of storage while these parameters remained unchanged in the thermally pasteurised juice with almost no microorganism growth. UV-irradiated pineapple juice preserved better quality attributes (TSS, pH, titratable acidity, ascorbic acid, turbidity, total phenolic, L (lightness), hue angle and chroma) than the thermal pasteurised juice during the storage time. Hence, UV irradiation has great potential as an alternative technology to thermal pasteurisation in producing products of high nutritive values.
Thermal treatment is commonly applied in juice manufacturing as a method to pasteurize juices. However the heat may deteriorate some of the essential compounds in the juice, especially heat-sensitive antioxidants. Therefore non-thermal treatment such as ultraviolet (UV) ray has been proposed as an alternative for pasteurization. The objective of this study was to compare the effect of thermal and UV treatments on the content of antioxidants (phenolic acids, flavonoids, carotenoids, ascorbic acids) and antioxidant capacity of single strength pineapple juice. The antioxidants stability of juices throughout 14 days of refrigerated storage was also studied. Ultraviolet treatment shows higher ascorbic acid content after treatment as compared to thermally treated single strength pineapple juice. Storage time affected the studied antioxidants, where UV
treatment provided better stability to ascorbic acid content while thermal treatment provided better stability to flavonoids and carotenoids.
Pasteurized shell eggs are eggs that have been thermally treated to eliminate harmful bacteria, however the treatment may also denature some of the egg white proteins. In this study the degree of denaturation and functional properties (emulsifying, foaming, and gelling properties) of egg white obtained from pasteurized eggs (EWP) were compared with those of unpasteurized eggs (EWUP). Data from differential scanning calorimeter showed that the EWP (ovotransferin, lysozyme, and ovalbumin) denatured at lower temperatures and required lower denaturation enthalpies than EWUP, indicating a partial loss of protein structure during the pasteurization process in the pasteurized eggs. The emulsion and foam stability formed from EWP were significantly (P < 0.05) lower than those of EWUP, however the EWP formed stronger gels than EWUP. To assess suitability of EWP as a cake ingredient, angel food cake was prepared using both egg whites. As compared to EWUP-cake, EWP-cake was significantly (P < 0.05) lower in volume, cohesiveness and springiness values, but significantly (P < 0.05) higher in hardness, gumminess and chewiness. Overall, the sensory panelists gave significantly (P < 0.05) higher scores for angel food cake prepared with EWUP. The differences in functional properties of egg white proteins and the quality of cake were due mainly to the higher levels of denaturation attained by EWP as a result of the pasteurization process.
Fresh-cut fruits and vegetables are the main sources of foodborne illness outbreaks with implicated pathogens such as Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes. This study aimed at investigating the influence of two key parameters (concentration of curcumin and illumination time) on the effects of curcumin-based photodynamic sterilization on the preservation of fresh-cut Hami melons. The results indicated that illumination with 50 μmol/L curcumin for 60 min using a blue LED lamp reduced the total aerobic microorganism count by ~1.8 log CFU/g in fresh-cut Hami melons. Besides this, the effects of photodynamic sterilization on the soluble solids content, color, water content, firmness, and sensory indices of the fresh-cut Hami melons were also evaluated. Compared to the control group, photodynamic sterilization can effectively delay the browning rate and maintain the luminosity, firmness, water content, and soluble solids content of fresh-cut Hami melon. The sensory quality was indeed preserved well after 9 days of storage in a fridge. These results showed that photodynamic sterilization is an effective and promising technology to prolong the shelf life of fresh-cut Hami melons.
The purpose of this study was to evaluate fermentation of milk in the presence of green tea (Camellia sinensis) with respect to changes in antioxidant activity, phenolic compounds and the growth of lactic acid bacteria. Pasteurized full fat cow's milk and starter culture were incubated at 41 °C in the presence of two different types of green tea extracts. The yogurts formed were refrigerated (4 °C) for further analysis. The total phenolic content was highest (p
Red-fleshed dragon fruit (Hylocereus polyrhizus) is rich in antioxidants. The aim of this study was to determine the effects of heat pasteurization, pH adjustment, ascorbic acid addition as well as storage under agitation and light or dark condition on betacyanin content in red-fleshed dragon fruit (Hylocereus polyrhizus) juice and concentrate. The concentrate was produced by concentrating clarified red-fleshed dragon fruit juice in a rotary evaporator at 40 °C. UV-Visible spectrophotometer was used for analyzing betacyanin content. Addition of 0.25 % ascorbic acid, pH 4.0, and pasteurization at 65 °C for 30 min were selected as the best processing conditions to retain betacyanin content in red-fleshed dragon fruit juice. Storage at the agitation speed of 220 rpm showed that the concentrated samples had higher betacyanin stability compared to juice, while both juice and concentrate had almost similar betacyanin stability when tested for storage in the presence of light. In summary, ascorbic acid stabilized betacyanin in both juice and concentrate at agitated or non-agitated conditions. In contrast, light degraded betacyanin in both juice and concentrate models.
The present work investigated the impact of several juice extraction methods (blender,
centrifugal juicer, and slow juicer) and thermal pasteurisation (72°C, 15 s) on the different
properties [physicochemical, polyphenol oxidase (PPO) activity, and functional] of
Clinacanthus nutans juice mix during storage (28 d, 4°C). Regardless of juicing technique, all
juices had similar colour and antioxidants [tested using 2,2-diphenyl-1-picrylhydrazyl
(DPPH) and ferric reducing antioxidant power (FRAP) methods]. The juices also had similar
PPO activity and sensory acceptance in terms of colour, aroma, flavour, mouthfeel, and
overall acceptability. The blender yielded juice with higher pH, soluble solids, and relative
viscosity than other methods. The slow juicer was the best at retaining ascorbic acid (39.33 ±
3.06 mg/100 mL), while the blender was best at retaining phenolic compounds (11.82 ± 0.12
mg gallic acid equivalents/100 mL) and chlorophyll (6.95 ± 0.31 μg/mL). Pasteurisation
negatively affected the colour, functional properties, and sensory characteristics (colour,
aroma, flavour, and mouthfeel) of the juice.
Bioinformatics tool is a software program made to extract meaningful information from the mass of molecular biology or biological databases and carry out sequence or structural analysis. The method of determining the order of nucleotides within a deoxyribonucleic acid (DNA) molecule is known as DNA sequencing. This analysis is meant to be run to the commercialized or factorymade goat's milk (pasteurised) from various states in Malaysia to identify the milk's authenticity, either it is pure or mixed with other foreign substances from other animals. The main objective is to compare DNA sequences of commercialized and raw goat's milk (handmilking and non-pasteurised). To achieve this, we used ClustalX to align and compare the obtained DNA from both milk samples. The sequences will be aligned using ClustalX software. ClustalX is a provider of an automated system for performing multiple alignments of sequences and profiles and evaluating the outcomes. The usage of ClustalX is helpful as it is cost-effective, user-friendly, and showing a high accuracy of the analysis.
This paper reports the design of an electronic nose (E-nose) prototype for reliable measurement and correct classification of beverages. The prototype was developed and fabricated in the laboratory using commercially available metal oxide gas sensors and a temperature sensor. The repeatability, reproducibility and discriminative ability of the developed E-nose prototype were tested on odors emanating from different beverages such as blackcurrant juice, mango juice and orange juice, respectively. Repeated measurements of three beverages showed very high correlation (r > 0.97) between the same beverages to verify the repeatability. The prototype also produced highly correlated patterns (r > 0.97) in the measurement of beverages using different sensor batches to verify its reproducibility. The E-nose prototype also possessed good discriminative ability whereby it was able to produce different patterns for different beverages, different milk heat treatments (ultra high temperature, pasteurization) and fresh and spoiled milks. The discriminative ability of the E-nose was evaluated using Principal Component Analysis and a Multi Layer Perception Neural Network, with both methods showing good classification results.
This intended paper was done to give an early overview of the expected quality attributes of pineapple-mango juice blend treated with ultraviolet irradiation (UV-C) and thermal pasteurisation. Josapine pineapple (Ananas comosus L.) and Chokanan mango (Mangifera indica L.) is the popular tropical fruits in Malaysia with unique taste and constant availability. The blend of pineapple-mango juice predicted to have good overall quality attributes as proved by prior studies on orange-pineapple, lemon-melon, pineapple-carrot-orange and carrot-apple-banana juice blends. Conventional thermal pasteurisation widely implemented in juice industry but resulted in massive quality degradation. Thus, research on the non-thermal technology of UV-C widely studied to overcome such drawbacks of thermal pasteurisation. Effect of UV-C and thermal pasteurisation on pineapple-mango juice blend will be evaluated in terms of physicochemical (pH, titratable acidity, total soluble solids, turbidity and colour), antioxidant (ascorbic acid, total phenolics content and total antioxidant DPPH assay) and microbiological properties. UV-C treated pineapple-mango juice blend believed to have better retention of heat sensitive ascorbic acid and other quality compared heat pasteurised juice with minimal distinctive characteristic compared to fresh juice.
Two experiments were carried out to evaluate the bactericidal impacts of Bacillus amyloliquefaciens CECT 5940 on the shedding of faecal pathogenic bacteria in dairy calves (Experiment 1) and in adults dogs (experiment 2). In the calves experiment, a completely randomized design was used to investigate the faecal bacteria profile of Holstein dairy calves fed with either pasteurized waste milk (PWM; n = 9) or a formulated non-medicated milk replacer (NMR; n = 9) for 60 d. The NMR containing sodium-butyrate and the active probiotic B. amyloliquefaciens CECT 5940. In the dogs experiment, addition of same probiotic (i.e., B. amyloliquefaciens CECT 5940) was carried out in two stages. The first stage started from day 7-37, and the second from day 44-71. The assessment of faecal score measured on day 22, 37, 42, 57, 71 and 77 to determine the texture of the stools. Calves received PWM consumed (P