Time Pasteurization Research Articles

Effects of high temperature short time (HTST) pasteurization on milk and whey during commercial whey protein concentrate production

Two pasteurization steps are often used in the preparation of whey protein concentrate (WPC) before evaporation into a dry product. The Pasteurized Milk Ordinance (PMO) in the United States requires that raw bovine milk be pasteurized using a process that meets minimum heat treatment requirements to achieve reductions in pertinent microorganisms. In addition, WPC produced from USDA-approved plants must comply with CFR Subpart B §58.809, which dictates that all fluid whey used in the manufacture of dry whey products shall be pasteurized before being condensed. These heat treatments are effective at inactivating the most thermally resistant bacterium, such as Coxiella burnetii; however, they can also alter milk proteins-inducing denaturation, aggregation and reduced bioactivity. Though the impact of thermal treatments on whey proteins has been examined, the specific influence of 2 high-temperature-short-time (HTST) pasteurization steps on the retention of proteins in WPC remains unknown. This study aimed to investigate the effect of commercial-scale HTST pasteurization of both raw milk and the resulting sweet whey on the products' overall protein profile. Three distinct batches of raw milk (RM) and corresponding pasteurized milk (PM), the resulting whey (RW) and pasteurized whey (PW) produced at commercial scale were analyzed. Assessments of denaturation were conducted through solubility testing at pH 4.6 and hydrophobicity evaluation via anilinonaphthalene-1-sulfonic acid assay (ANS). Additionally, enzyme-linked immunosorbent assay (ELISA), PAGE (PAGE) and liquid chromatography tandem mass spectroscopy (LC-MS/MS) were employed to compare the retention of key bioactive proteins before and after each HTST pasteurization step. The percentage of soluble whey protein decreased from RM to PM and from RW to PW, but no significant differences were observed via hydrophobicity assay. ELISA revealed a significant reduction in key bioactive proteins, such as lactoferrin, immunoglobulin A and immunoglobulin M, but not immunoglobulin G, after HTST pasteurization of RM and RW. PAGE and LC-MS/MS revealed a significant decrease in the retention of lactoferrin and key milk fat globular membrane proteins, such as xanthine dehydrogenase oxidase/xanthine oxidase, lactadherin and fatty acid binding protein. Additionally, xanthine oxidase activity was significantly reduced after HTST pasteurization of milk and whey. This research helps to identify the limitations of the current processing techniques used in the dairy industry and could lead to innovation in improving the retention of bioactive proteins.

Ultrafiltration: Impact of process temperature (7 and 50°C) on process performance and protein beverage physical, chemical, and sensory properties.

Our objectives were to determine the impact of ultrafiltration (UF) of skim milk at 7 and 50°C on UF processing, lactose removal, mineral partitioning, and skim milk retentate physical, chemical, and sensory properties at 3 (3.4 7.5, and 10.5%) protein concentration with 2 different heat processing treatments high temperature short time (HTST) pasteurization and autoclave). Pasteurized skim milk was split into 2 portions and the 7°C UF processing run was done on one day and the 50°C UF processing run was done on the next day. Skim milk was ultrafiltered and diafiltered at 7 and 50°C and as permeate was removed, deionized water at 7 or 50°C was added in an equal amount by weight as permeate removed to maintain constant protein concentration in the retentate during UF until 98% or more of lactose and low molecular weight soluble milk components were removed. All skim milk-based beverage bases from the 7 and 50°C UF of skim milk were HTST (78°C for 15 s) processed or autoclaved (116°C for 6 min). The physical, chemical, and sensory properties of all treatments were measured. This process was replicated twice with a new batch of pasteurized skim milk in a different week with the 7 and 50°C UF processing runs ran in reverse order. Overall, lactose-free skim milk at 3.4, 7.5, and 10.5% protein produced by UF with DF, was more bland, more white and less heat stable (i.e., stable to retorting but not direct steam injection at 142°C for 2 to 3 s) than skim milk based on both sensory scores and instrumental measures. A 98 to 99% removal of lactose from skim milk was achieved (final lactose concentration <0.06 g/100g) with a diafiltration ratio of water to milk of about 4 to 1 was used at both 7°C and 50°C. The processing time to achieve that lactose removal from the same starting weight of milk was about twice as long when filtering at 7°C than 50°C because of the lower flux (23 versus 48 kg/m2/h). The continuous DF at constant protein concentration maintained constant flux for a processing time of 4 and 8 h at 50 and 7°C, respectively. The final freezing point of the lactose and soluble mineral reduced milk was close to that of water (-0.015°C versus -0.525°C for skim milk) and the pH of the lactose-free milk at 20°C increased from about 6.5 for skim to about 7.33 and 7.46 for UF/DF skim milk at 7 and 50°C, respectively. Removal of compounds that absorb light (in the range of 360 to 500 nm) from milk in the permeate, increased light reflectance and whiteness and decreased yellowness relative to the starting skim milk.

Effect of pasteurization time and temperature on the physico-biochemical properties of soursop (Annona muricata L.) juice

This study aimed to determine the effect of pasteurization time and temperature on soursop juice characteristics. Soursop (Anonna muricata L.), a climacteric fruit, is a high source of natural antioxidants and contains polyphenol oxidase (PPO) enzyme, which causes browning and can reduce the phenol content in fruit which can reduce antioxidant activity. The pasteurization process was carried out to inactivate PPO in soursop juice production. Soursop juice was prepared from soursop fruit pulp pasteurized at temperatures (56, 62, 68, 74, and 80 oC) for various pasteurization times (5, 10, and 15 minutes). Time and temperature of pasteurization had a significant effect (ρ &lt; 0.05) on physical characteristics (Total Soluble Solid/TSS, viscosity, pH, and colour), polyphenol oxidase enzyme activity, antioxidant activity, and microbial population. Pasteurization at 62 ˚C for 5 minutes can maintain antioxidant activity with the greatest total phenol of 85.45 ± 3.5 mg GAE/100 g, total flavonoid of 71.38 ± 6.9 mg QE/100 g, and antioxidant activity of 76.91 ± 0, 33%. Pasteurization at 80 ˚C for 15 minutes can reduce the total number of bacteria from 350 ± 24 CFU/mL to 54 ± 22 CFU/mL, which has a TSS value of 13.73 ˚brix, viscosity of 928.67 mPa, pH of 4.40, a total colour change of 0.556, and has the lowest PPO enzyme specific activity of 0.0005 U/mg with enzyme inactivation of 93%.

Evaluation of the thermal degradation kinetics of vitamin C in the pulp of tumbo (Passiflora mollissima b.)

Vitamin C is an important micronutrient, which is found in acidic fruits such is the case of tumbo, studies have shown beneficial effects of vitamin C on health due to its antioxidant and free radical scavenging capabilities. The objective of the research was to evaluate the thermal degradation kinetics of vitamin C of the pulp of tumbo (Passiflora mollissima b.). The pulp of tumbo was prepared and subsequently subjected to different temperatures (60, 70 and 80 ° C) and times (0, 5, 10, 15 and 20 min). The vitamin C content in the pulp of tumbo was 77.01 mg / 100g which was analyzed by spectrophotometry. The results showed that vitamin Cdegradation followed second-order kinetic models. The degradation rate constants for ascorbic acid in the tumbo pulp were: k60 = 0.014 min-1, k70 = 0.019 min-1 and k80 = 0.023 min-1 and the decimal reduction times are: D60 = 162.17 min, D70 = 121.74 min and D80 = 101.76 min. The z value was 99 ° C, the Ea in the temperature range of 60-80 ° C is 22.84 kJ / mol and the value of Q10 is 1.60. The optimal time and temperature of pasteurization in the pulp of tumbo is 10.69 min at 60 ° C, for presenting the best correlation index, retaining the greatest amount of ascorbic acid, presenting a lower reaction rate and requiring a longer time of decimal reduction. It was concluded that the higher the temperature, the higher the degradation of vitamin C, the data obtained will help to predict the best conditions of processing of the pulp of tumbo and minimize degradation since it is an important quality factor.

Comparative study on microbiological, physicochemical and nutritional properties of whole cow milk by thermal and non-thermal processing technologies

The majority of the bioactive components in milk exhibit sensitivity to heat treatments. This research is the first systematically compare the effects of thermal (low-temperature long time pasteurization, LTLT; high-temperature short time pasteurization, HTST; ultra-high temperature, UHT; microwave-assisted heating; retort sterilization) and non-thermal (ultraviolet-C, UV-C; high hydrostatic pressure processing, HPP; filtered sterilization; high-intensity ultrasound, HIUS) treatments on the physicochemical properties and immune-active serum proteins of whole milk aliquots under the equivalent microbicidal efficacy. LTLT and HTST had little impact on whole milk. HPP at 400 MPa for 5 min was an optimal alternative to pasteurized milk in terms of equivalent microbicidal efficacy, higher nutrient retention (∼6% and 16.2% loss for IgG and lactoferrin) and fewer oxidation products (0.69 nmol/mg protein carbonyls). The serum protein denaturation of 600 MPa HPP-treated milk (79.4% and 31.36% loss for IgG and lactoferrin) was significantly higher than in pasteurized milk, but still lower than in UHT milk (97.16% and 70.85% loss for IgG and lactoferrin). Since photo-oxidation induced by high-dose irradiation was detrimental to the organoleptic properties, relying on UV-C as stand-alone replacement to pasteurization is not advisable. Combined with existing pasteurization methods, UV-C can achieve superior microbial inactivation at mild sterilization temperatures. HIUS, a promising novel tool, should be further optimized regarding the relevant standards to enable it to be used in industrial-scale processing and reproducibility. Compared with traditional thermal treatments, non-thermal strategies offer a significant reduction in the microbial load of raw milk while better preserving bioactive proteins, However, optimizing processing parameters remains essential to strike a balance between microbial inactivation and retention of active substances.

Effect of pasteurization time and temperature on bioactive compounds, antioxidant ability and color value of beverage produced from herbal extract (Passiflora foetida and embryo nelumbinis)

Herbal beverage is one of the natural products which are greatly preferred by customers. Passiflora foetida and Embryo Nelumbinis are two kinds of medicinal plants that possess many precious bioactive compounds that have the effect of supporting calmness, reducing stress, treating insomnia; and have been used in many folk remedies in Vietnam. The main objective of this study is to investigate the effects of heating temperature (75, 85 and 95°C) and pasteurization time (15, 30, 45 and 60 minutes) on the content of bioactive compounds (polyphenol, flavonoid, tannin, alkaloid and saponin), antioxidant ability (FRAP, DPPH) and color parameters (L*, a*, b* and ΔE) of product. The reseach was designed randomly with two factors and three replications. The content of bioactive compounds and antioxidant capacity of product were analyzed by standardization methods using spectrophotometer; and the color parameters were measured by the colorimeter. The result showed that the opitmal pasteurization temperature and time were 85°C and 30 minutes, at this heating process the product maintained high level of bioactive compounds and antioxidant ability. The content of polyphenol, flavonoid, tannin, saponin and alkaloid were 9.46 mgGAE/g, 4.44 mgQE/g, 4.85 mgTAE/g, 7.40 mgSE/g, 14.25 mgCE/g; the antioxidant capacity of product by DPPH and FRAP method were 64.50% and 28.25 μFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as L*, a*, b* and ΔE were 31.58, -0.24, -0.47 and 61.25, respectively. The production process was successful in pilot equipment and the product can be used as one of the beverages for health strengthening.

High hydrostatic pressure combined with high-temperature short time pasteurization improves the quality characteristics and extends the shelf life of donkey milk

The processing method, which affects the quality and shelf life of dairy products, depends on the processing stability of raw milk. The effects of high-temperature short time pasteurization (HTST) at 75 °C/15 s and HTST plus high hydrostatic pressure (HHP) at 200, 300 and 400 MPa on the physical stability, soluble calcium and phosphorus concentrations, protein conformation and contents, and storage properties including microbiological characteristics, pH and sedimentation rate of donkey milk were investigated. HTST increased the particle size and lowered soluble calcium and phosphorus concentrations of donkey milk (P < 0.05). HTST plus HPP treatment at 200–400 MPa further increased the particle size and random coil, but decreased β-sheet and β-turn contents with the increasing pressure (P < 0.05). However, HTST plus HPP treatment at 400 MPa reduced the stability of the donkey milk. Moreover, HTST plus HPP treatment at 200–300 MPa preserved lysozyme, α-lactalbumin and β-lactoglobulin (P < 0.05). During the storage period, HTST plus HPP treatment at 300 MPa extended the shelf life by 85.71%, exhibiting stable pH and precipitation rate. It reduced the TMC, coliform and Staphylococcus aureus (P < 0.05). Therefore, our findings suggested HTST at 75 °C for 15 s plus HPP treatment at 300 MPa stabilizes the storage properties of donkey milk while maintaining quality characteristics.

Influence of matrix pH on batch thermal pasteurization of sweet lime juice: Global kinetic models for Saccharomyces cerevisiae and polyphenol oxidase inactivation and degradation of vitamin C

AbstractA set of experiments were conducted to screen the most thermo‐resistant microorganism and spoilage enzyme in sweet lime juice. Furthermore, the impact of matrix pH on the batch thermal treatment (75–95°C/0–10 min) intensities on Saccharomyces cerevisiae survival, PPO inactivation, and vitamin C retention in the sweet lime juice was evaluated. The influence of cumulative come‐up time (tCUT) and cooling time (tCOOL) was separated from the isothermal holding period (tHOLD). All three responses fitted best to the first‐order kinetics. The rate constants (k) ranged between 0.0053 and 0.471 s−1 (for S. cerevisiae), 0.00114 and 0.00731 s−1 (for PPO), and 0.000017 and 0.000142 s−1 (for vitamin C). The microbial and enzyme inactivation rate increased at a low pH level for a certain temperature, whereas, for vitamin C, an opposite trend was prominent through marginal. A new global kinetic model for k as a function of matrix pH and the temperature was developed in which the sensitivity of k to pH change was introduced as SpH. The optimized thermally pasteurized juice (95°C/298 s of holding time) at pH 3.5 showed &gt;5 log cycle reduction in S. cerevisiae count (t5D, s) and 99% inactivation in PPO activity (t99, s) while retaining 57% vitamin C and 39% loss in total phenolics. The optimally treated pasteurized sample at pH 3.5 was examined for phenolic profiling, microbial cell morphology, and enzyme conformational change. The thermally pasteurized sample had a sensory acceptance of 6.9 out of 9 scales.Practical applicationsThe present study developed a systematic study for designing a thermal pasteurization condition for sweet lime juice. First, the most thermo‐resistant microorganism and spoilage enzymes in sweet lime juice were screened out based on the sensitivity index. Further, a global kinetic model was developed for the most resistant microorganisms, resistant enzymes, and vitamin C. This model can describe the impact of matrix pH and temperature on the treatment time to achieve microbial safety and enzymatic stability. Pasteurization time was estimated for each combination of pH and temperature. Assessing the impact of pH levels in the matrix on the effectiveness of thermal pasteurization would assist the industry in determining optimal harvesting conditions for fruit with the desired pH.

Processors' understanding of process quality: a qualitative interview study with employees of organic dairies in Germany and Switzerland

PurposeOrganic food processing must include organic principles to be authentic. This qualitative study aims to understand the processors' understanding of organic food processing quality.Design/methodology/approachThis study is based on semi-structured expert interviews with eight employees of six purely or partly organic dairies from Germany and Switzerland. Interview themes are (1) quality of organic milk processing in general, (2) assessment of specific processing techniques, (3) product quality of organic milk and (4) flow of information between producer and consumer. The interviews have been audio-recorded, transcribed verbatim and thematically analysed.Findings(1) Experts prefer minimal processing; some prefer artisanal processing, whilst others stress the advantages of mechanisation. (2) High temperature short time (HTST) pasteurisation and mechanical processing techniques are accepted; ultra-high-temperature (UHT) milk processing is partly rejected. (3) Traditional taste and valuable ingredients should be present in the final product. Natural variances are judged positively. (4) Consumers' low level of food technology literacy is challenging for communication.Research limitations/implicationsThe results cannot be generalised due to the qualitative study design. Further studies, e.g. qualitative case analyses and studies with a quantitative design, are necessary to deepen the results.Practical implicationsThe paper shows which processing technologies experts consider suitable or unsuitable for organic milk. The paper also identifies opportunities to bridge the perceived gap between processors' and consumers' demands.Originality/valueThe study shows the challenges of processors in expressing the processors' understanding of process quality.

Different Treatments for Sugarcane Juice Preservation.

This investigation aimed to optimize the time, pH, pressure, and temperature of sugarcane juice pasteurization and to develop a "ready to serve" bottled sugarcane juice with a high preservation efficiency. Fresh sugarcane juice was extracted from sugarcane genotype Co 89003, and beverage samples were collected using three different treatments: sulphitation of juice with the addition of potassium metabisulphite (KMS-25, 50, 100, and 150 ppm), acidification of juice (addition of citric acid, to reduce the pH of the juice to 4.8, 4.5, and 4.25), and steam treatment of the canes (5 min, 10, and 15 min at 7 psi). In all treatments, the juice was pasteurized in glass bottles @ 65 °C for 25 min and stored at low temperature (5 °C) in pre-sterilized glass bottles. Juice properties such as the ˚Brix, total sugar, pH, and total phenolic content decreased with storage, whereas the microbial count, titrable acidity, and reducing sugar content significantly increased during storage. The addition of KMS, citric acid, and the steam treatment reduced the browning of juice and maintained the color of juice during storage, by inhibiting the polyphenol oxidase enzyme activity, from 0.571 unit/mL to 0.1 unit/mL. Among the selected treatments, sugarcane juice with KMS (100 and 150 ppm) and steam treatment of the canes for 5 and 10 min at 7 psi showed the minimum changes in physico-chemical properties, sensory qualities, and restricted microbial growth. Thesulphitation treatment with pasteurization proved best for increasing the shelf life of sugarcane juice upto 90 days with refrigeration. Similarly, the steam-subjected cane juice (10 and 15 min at 7 psi) could be effectively preserved for upto 30 days with refrigeration, without any preservative.

PENGARUH KOMBINASI PROSES TERMAL DAN JENIS KEMASAN TERHADAP MUTU CIMPLUNG SINGKONG SIAP SAJI

Cassava cimplung is a traditional processed food made from cassava which is boiled in coconut sap water. Cassava has not been widely produced in ready-to-eat packaging as a selling value food. This is because cimplung is a semi-wet food so it easily spoils and does not last long. In an effort to maintain the quality of cassava cimplung, in this study a thermal pasteurization process was carried out with variations in the length of 10 minutes and 15 minutes and the use of EVOH (Ethylene Vinyl Alcohol) and boilpack packaging. Quality parameters observed included texture, pH, color, and brix content for 6 weeks of storage. The aims of this study were 1) To determine the effect of packaging type on the quality of cassava cimplung, 2) To determine the effect of pasteurization time on the quality of cassava cimplung, and 3) To determine the interaction effect of packaging type and pasteurization duration on the quality of cassava cimplung. The results of this study were 1)The treatment of the type of packaging was significantly different on the value of texture, pH, and color but was not significantly different on the brix content of cassava cimplung, 2) Pasteurization time treatment was significantly different to color value but not significantly different to texture, brix content, and pH of cassava cimplung, and 3) The interaction between the type of packaging and the duration of pasteurization was not significantly different on all quality parameters of cassava cimplung

A new decontamination method for Bacillus subtilisin pasteurized milk: Thermosonication treatment

Thermosonication (TS) is a novel and viable technique employed to replace conventional thermal processing. TS treatment combined with pasteurization was used to kill the residual heat-resistant Bacillus in pasteurized milk and extend the shelf life of pasteurized milk and compared with High Temperture Shoort Time (HTST) pasteurization to study its decontamination effect on Bacillus subtilis and the quality of treated milk. The results showed that after 40 kHz, 240 W, 25 min ultrasonic treatment and 50 °C heating decontamination treatment, the number of B. subtilis in the medium and milk medium decreased by 4.17 log CFU/mL and 4.09 log CFU/mL respectively. The results of cell membrane permeability showed that the leakage of DNA and protein in the HTST-TS group increased by 52.3 % and 34 %, respectively, when compared to that in the HTST group. In addition, transmission electron microscopy (TEM) analysis showed that the bacterial cell membrane of the HTST-TS group swelled up, the cell wall was ruptured, and the cell content was accumulated in the cells. The results showed that HTST-TS treatment significantly inhibited the activities of ATPase (47 %), succinate dehydrogenase (SDH) (68.6 %), and malate dehydrogenase (MDH) (54.4 %). The physical and chemical sensory evaluation of milk treated with HTST-TS showed that HTST-TS treatment could improve the L* value (2.24 %), zeta potential (64.19 %), and colloidal particle size (14.49 %) of milk but had no significant effect on oral sensitivity. In conclusion, this study provides new insights, which may be helpful in implementing this new combined decontamination method in the dairy industry to improve the quality of pasteurized milk and extend the its shelf life.

Monte Carlo simulation model predicts bactofugation can extend shelf-life of pasteurized fluid milk, even when raw milk with low spore counts is used as the incoming ingredient.

Bacterial spores from raw milk that survive the pasteurization process are responsible for half of all the spoilage of fluid milk. Bactofugation has received more attention as a nonthermal method that can reduce the presence of bacterial spores in milk and with it the spoilage of fluid milk. The objective of this work was to determine the effectiveness of bactofugation in removing spores from raw milk and estimate the effect the spore removal could have on shelf-life of fluid milk. The study was conducted in a commercial fluid milk processing facility where warm spore removal was performed using one-phase bactofuge followed by warm cream separation and high temperature, short time pasteurization. Samples from different stages of fluid milk processing with and without the use of bactofuge were tested for total plate count, mesophilic spore count, psychrotolerant spore count (PSC), and somatic cell count. Results were evaluated to determine the count reductions during different stages of fluid milk processing and compare counts in fluid milk processed with and without bactofugation. Bactofugation on average reduced the total plate count by 1.81 ± 0.72 log cfu/mL, mesophilic spore count by 1.08 ± 0.71 log cfu/mL, PSC by 0.86 ± 0.59 log cfu/mL, and somatic cell count by 135,881 ± 43,942 cells/mL. Psychrotolerant spore count in final pasteurized skim milk processed with and without bactofugation was used to predict the shelf-life of the pasteurized skim milk using the Monte Carlo simulation model. Although PSC in the initial raw milk was already low (-0.63 ± 0.47 log cfu/mL), the predicted values from the simulation model showed that bactofugation would extend the shelf-life of pasteurized skim milk by approximately 2 d. The results of this study will directly help fluid milk processors evaluate the benefits of using bactofugation as an intervention in their plants, and also demonstrate the benefits of using mathematical modeling in decision making.

Advances in Food Pasteurization Techniques

In the recent years, the consumer has been demanding highly nutritious, minimally processed foods with a longershelf life. Thus began the need for reviewing and upgrading of traditional pasteurization techniques and the needfor developing of new technologies for the pasteurization of food. The pasteurization techniques are classified intothermal and non-thermal techniques. The aim of this review is to discuss A] Thermal pasteurization techniques:HTST (High Temperature and Short Time pasteurization, LTLT (Low Temperature and Long Time) Pasteurization, UHT (Ultra High Temperature) Pasteurization, Pasteurization by water bath, Steam Pasteurization, Vacuum SteamPasteurization, Infrared (IR) Heating Pasteurization, Microwave Heating Pasteurization, Dielectric (Radiofrequency)Heating Pasteurization. B] Non-Thermal Pasteurization Techniques: High Pressure Pasteurization (HPP) orHydrostatic High-Pressure Pasteurization, Irradiation Pasteurization, pulsed electric fields (PEF) Pasteurization, UV(Ultraviolet) Pasteurization, Cold Plasma Pasteurization, Ultrasound Pasteurization, Supercritical Gas (SC)Pasteurization, Oscillating Magnetic Field Pasteurization, Pulsed Light Pasteurization. All these pasteurizationtechniques have their own advantages and limitations, so according to the characteristics of the food, one needs towisely choose the technique. Non-thermal techniques are not in use despite their minimal processing andpreservation of food quality attributes because they are expensive and complex with respect to thermaltechniques.

Fouling mechanisms of coconut milk foulants formed during pasteurization

This work aimed to study mechanisms of coconut milk fouling by studying major components found in coconut milk foulants, namely proteins and fats, generated at various pasteurization times. Both batch (BP) and continuous pasteurizations (CP) were studied. Similar results were observed from the BP and CP. Mass of foulants increased with pasteurization times (5–25 min). In addition, masses of proteins and fats increased with pasteurization time. Although, the mass of fats found in CP foulants increased slightly, mass of both types of foulants linearly correlated with masses of proteins and fats. SEM images of coconut milk foulants showed that fouling occurred within one minute of pasteurization. The images together with content analysis of the foulants demonstrated that the foulants may composed of few layers together and an initial layer of foulants was composed of proteins, carbohydrates, fats, and minerals. Emulsion sizes of pasteurized coconut milk increased with the pasteurization time. Hence, the coconut milk fouling mechanisms may initially start by deposition of denatured protein and other components in water phase of the milk onto heat transfer surfaces. The deposition of proteins together with denaturation of proteins, which act as emulsifiers of the milk, caused instability of the coconut emulsion. Therefore, the increased coconut oil droplet sizes during pasteurization were observed. Consequently, fat and carbohydrate attached to fat could deposit into and onto the fouling layers. Although fouling mechanisms of BP and CP foulants were similar, the different flow schemes affected the compositions, appearances, and strengths of the two foulants. These in turn affect cleaning behaviours of the two foulants.

Improving the microbial and nutritional quality of skim milk using microfiltration combined with thermal and nonthermal techniques

The effectiveness of microfiltration (MF), alone or combined with high temperature short time (HTST) pasteurisation, ultraviolet-C (UV-C), and ultrasonication (US) in improving the microbial and nutritional quality of skim milk was evaluated in comparison with commercial ultra-pasteurisation (UP). Compared with untreated skim milk, MF combined with UV-C and US retained more bioactive proteins, which made these techniques superior to MF combined with HTST. Almost no bioactive proteins survived after UP. MF alone reduced the bacterial load by 2.5 log; however, MF combined with HTST (MH), UV-C (MUV), or US (MUS) can reduce the bacterial load to an undetectable level and extend the microbial shelf-life of skim milk to 40 days. In addition, MUV and MUS did not induce significant protein oxidation. Even though the skim milk after MUV or MUS showed only minor microbial growth, the shelf-life was limited by proteolysis through plasmin activity.

Optimization of formulation and process conditions of chestnut-based functional beverage using response surface methodology.

Response surface methodology was used to optimize the chestnut beverage production under the effect of the independent variables including dilution rate (x 1 ), dilution temperature (x 2 ), pasteurization time (x 3 ) and pasteurization temperature (x 4 ). The experiments were based on a central composite design with linear and quadratic models employed to study the combined effects of four independent variables. The responses were selected with functional properties such as antioxidative attributes and total phenolic content. The optimal conditions (x 1 , x 2 , x 3 and x 4 ) determined for development of chestnut based functional beverage were a dilution rate of 25.19g/100 mL, a dilution temperature of 37.562°C, a pasteurization time of 24.996min. and a pasteurization temperature of 84.433°C. After comparing the predicted and experimental results, the multi-response surface methodology was more stable with a good correlation for a functional chestnut beverage.

Pengaruh Waktu Pasteurisasi Terhadap Cemaran Mikrobiologis dan Aktivitas Antioksidan Loloh Daun Pohpohan (Pilea trinervia Wight.)

&#x0D; &#x0D; &#x0D; Loloh is one of the traditional beverages in Bali made from fresh leaves, root, stem, seeds or fruit without cooking treatment (cold process). Some studies showed that loloh in several area in Bali is not worth to consume because of high level of microbial contamination. This study aimed to determine the effect of pasteurization time to produce loloh pohpohan leaves with the best antioxidant activity and free from microbial contamination. This experiment used a Completely Randomized Design with 7 variations of pasteurization treatment time, namely 0, 10, 15, 20, 25 30 and 35 minutes. The treatment was repeated three time for obtain 21 experimental units. The data obtained were analyzed by analyze of variance and if the treatment had significant effect, then it was followed by Duncan Multiple Range Test (DMRT). The result of this study showed that pasteurization time has a very significant effect (P&lt;0,01) on total microbial, total coliform and antioxidant activity. The best loloh treatment in this study was obtain with 20 minutes pasteurization time with the total plate count 0 CFU/mL (no microbes showed), negative coliform and antioxidant activity 58.39% with IC50 valued 1584.097 ppm, the color is neutral, the aroma is neutral, the taste was bitter and neutral and overall acceptance&#x0D; is neutral.&#x0D; &#x0D; &#x0D;

Quality Analysis of Yoghurt from Goat's Milk Using Starter Lactic Acid Bacteria

Yoghurt is a pro-biotic beverage produced from the fermentation process of milk, namely from vegetable milk (soy milk) or animal milk (goat's milk and cow's milk). During the fermentation process, the chemical reactions that occur will turn milk into yogurt with the help of lactic acid bacteria. In the health sector, yogurt plays a role in increasing the body's immunity, digestive tract health and can prevent osteoporosis. In general, yogurt circulating in the community still has low nutritional content, so a more in-depth study needs to be done. The goal of this research is to examine the quality of yogurt by manipulating certain variables and adding other components to increase the yogurt's quality. Streptococcus thermophilus and Lactobacillus bulgaricus were used as starter as much as 12.5 mL each (10% of 500 mL of cream milk). The fixed variables in this study were the volume of goat's milk 500 ml, cream concentration 6%, pasteurization temperature 85°C, pasteurization time 15 minutes and fermentation temperature 45°C, while the independent variables were varying the length of the fermentation process for 3, 4, 5, 6, 7, 8 and 9 hours. From this study, it was concluded that yogurt with optimum results was obtained at a fermentation time of 6 hours, the pH value was 3.8, lactic acid content was 1.305%, protein content was 5.54%, fat content was 4.98%, and moisture content was 84.10%.

Optimization of temperature and pasteurization time of soursop juice (Annona muricata) by response surface methodology in pilot scale

Interest in soursop and its derivatives has increased over time, with many scientific articles reporting its health benefits. Several recent studies reported the presence of bioactive compounds and phytochemicals from soursop juice. However, climatic fruit tends to have different post-harvest handling than others. A series of processes from harvesting to extraction played an important role in its final product. The thermal inactivation of the PPO enzyme, which causes brownish color, can be used to improve the quality of soursop juice. This process can be carried out using the MTLT (Mild Temperature Long Time) pasteurization process using a customized double jacket heater by considering the thermoresistence properties of bioactive compounds in soursop juice. This study aims to determine the optimal formulation for process parameters also provide the optimal choice for the pasteurization process in pilot scale and database for the transition to industrial production. Response Surface Methodology (RSM) was a method used to optimize the process and formulation of soursop fruit juice. In this study, two factors were used, namely pasteurization temperature (56-80 °C) and heating time (5-15 min) obtained by previous research to determine the most optimal total Total Phenolic Content (TPC), Total Flavonoid Content (TFC), Color measurement, Total Dissolve Solid and Viscosity.