Equivalent processing for pasteurization of a pineapple juice-coconut milk blend by selected nonthermal technologies.

Identifying equivalent processing conditions is critical for the relevant comparison of food quality attributes. This study investigates equivalent processes for at least 5-log reduction of Escherichia coli and Listeria innocua in pineapple juice-coconut milk (PC) blends by high-pressure processing (HPP), pulsed electric fields (PEF), and ultrasound (US) either alone or combined with other preservation factors (pH, nisin, and/or heat). The two blends (pH 4 and 5) and coconut milk (pH 7) as a reference were subjected to HPP at 300-600 MPa, 20°C for 0.5-30 min; PEF at an electric field strength of 10-21 kV/cm, 40°C for 24 µs; and US at 120 µm amplitude, 25 or 45°C for 6 or 10 min. At least a 5-log reduction of E. coli was achieved at pH 4 by HPP at 400 MPa, 20°C for 1 min; PEF at 21 kV/cm, 235 Hz, 40°C for 24 µs; and US at 120 µm, 45°C for 6 min. As L. innocua showed greater resistance, a synergistic lethal effect was provided at pH 4 by HPP with 75 ppm nisin at 600 MPa, 20°C for 5 min; PEF with 50 ppm nisin at 18 kV/cm, 588 Hz, 40°C for 24 µs; and US at 45°C, 120 µm for 10 min. The total soluble solids (11.2-12.4°Bx), acidity (0.47%-0.51% citric acid), pH (3.91-4.16), and viscosity (3.55 × 10-3 -4.0 × 10-3  Pa s) were not significantly affected under the identified equivalent conditions. HPP was superior to PEF and US, achieving higher ascorbic acid retention and lower color difference in PC blend compared to the untreated sample.

High-pressure pasteurization of low-acid chilled ready-to-eat food.

The working population growth have created greater consumer demand for ready-to-eat (RTE) foods. Pasteurization is one of the most common preservation methods for commercial production of low-acid RTE cold-chain products. Proper selection of a pasteurization method plays an important role not only in ensuring microbial safety but also in maintaining food quality during storage. Better retention of flavor, color, appearance, and nutritional value of RTE products is one of the reasons for the food industry to adopt novel technologies such as high-pressure processing (HPP) as a substitute or complementary technology for thermal pasteurization. HPP has been used industrially for the pasteurization of high-acid RTE products. Yet, this method is not commonly used for pasteurization of low-acid RTE food products, due primarily to the need of additional heating to thermally inactivate spores, coupled with relatively long treatment times resulting in high processing costs. Practical Application: Food companies would like to adopt novel technologies such as HPP instead of using conventional thermal processes, yet there is a lack of information on spoilage and the shelf-life of pasteurized low-acid RTE foods (by different novel pasteurization methods including HPP) in cold storage. This article provides an overview of the microbial concerns and related regulatory guidelines for the pasteurization of low-acid RTE foods and summarizes the effects of HPP in terms of microbiology (both pathogens and spoilage microorganisms), quality, and shelf-life on low-acid RTE foods. This review also includes the most recent research articles regarding a comparison between HPP pasteurization and thermal pasteurization treatments and the limitations of HPP for low-acid chilled RTE foods.

Shelf life extension of strawberry juice by equivalent ultrasound, high pressure, and pulsed electric fields processes.

Nonthermal processing technologies have focused on the production of safe, fresh-like and high quality food products very much in line with current consumer demands. It is a high priority to maintain the quality attributes of the food during its shelf life. In this study; microbial stability, physicochemical properties and phytochemical characteristics of strawberry juice (SJ) pasteurized by ultrasonication (US) (55 °C, 0.29 W/mL acoustic energy density, 120 µm amplitude, 3 min), high pressure processing (HPP) (300 MPa, 1 min), and pulsed electric fields (PEF) (35 kV/cm, 27 µs) were evaluated during 42 days of storage at 4 °C in comparison with conventional thermal pasteurization as a reference treatment (72 °C, 15 s). The nonthermal processes were equivalent in terms of E. coli inactivation since the selected processing conditions previously led to almost identical inactivation level (at least 5-log) of inoculated E. coli. Thus, the current study demonstrates how these equivalent US, HPP, and PEF treatments differ from each other in terms of their effect on SJ natural microbiota and quality characteristics during refrigerated storage. Results showed that US, HPP, and heat treatment ensured the microbial stability of SJ for at least 42 days while PEF extended the shelf life of SJ by at least 28 days based on the natural microbiota. No significant difference was found for the total soluble solids of the processed samples (p > 0.05) whereas acidity and pH of the samples varied during the storage period (p < 0.05). Immediately after processing, the total phenolic contents and antioxidant activities of SJ were better retained by HPP and PEF compared to thermal pasteurization. Furthermore, HPP and PEF significantly increased total anthocyanin content of SJ by 15 and 17% with respect to untreated SJ (p < 0.05). Phytochemical characteristics of processed SJ started to decrease after 7 days of storage irrespective of treatment type. HPP treated juices showed significantly higher levels of total anthocyanin and antioxidant activity at the final day of storage. Principal component and cluster analysis showed that the processed SJ samples had higher similarity to the untreated fresh SJ during storage up to 14 days, while the samples beyond this storage period clustered together and discriminated from the rest indicating a decreased similarity to the fresh juice. This study rendered simultaneous evaluation of several quality characteristics during storage of pasteurized strawberry juice based on the equivalent processing approach and multivariate data analysis. Under the selected processing conditions, HPP was the best option to extend the shelf life of SJ and enhance its phytochemical characteristics.

Influence of low water activity on the thermal resistance of Salmonella Enteritidis PT30 and Enterococcus faecium as its surrogate in egg powders.

Egg powders are increasingly popular ingredients, due to their functionality and compactness, in industrial food production and preparation at homes. However, there is a lack of studies that evaluate the thermal resistance of Salmonella Enteritidis PT30 and its potential surrogate Enterococcus faecium NRRL B-2354 in egg powders. This study examined the log-linear relationship between the thermal resistance of Salmonella Enteritidis (D-value) and the water activity (aw) of egg powders. The changes of aw in the egg powders with temperature were measured using a Vapor Sorption Analyzer and a high-temperature cell. The D80 ℃-value of S. Enteritidis PT30 and E. faecium inoculated in the egg powders preconditioned to three aw levels (0.3, 0.45, and 0.6) at 20 ℃ were determined using aluminum thermal death test cells. The aw values increased (P < 0.05) in all three egg powders when the temperature of the samples was raised from room temperature to 80 ℃. The D80 ℃-values ranged from 5.3 ± 0.1 to 25.9 ± 0.2 min for S. Enteritidis while 10.4 ± 0.4 to 43.8 ± 0.4 for E. faecium in samples of the three different aw levels. S. Enteritidis PT30 showed a log-linear relationship between D80 ℃-values and aw80 ℃ for the egg powders. This study contributes to our understanding of the impact of aw on the development of thermal treatments for low-moisture foods.

Interlaboratory Measurement of Rheological Properties of Tomato Salad Dressing.

Rheological properties of food materials are important as they influence food texture, processing properties, and stability. Rotational rheometry has been widely used for measuring rheological properties. However, the measurements obtained using different geometries and rheometers are generally not compared for precision and accuracy, so it is difficult to compare data across different studies. In this study, nine rheometers from seven laboratories were used to measure the viscosity and viscoelastic properties of a commercial salad dressing. The measurements were obtained at three temperatures (8, 25, and 60 °C) using different diameter parallel plates (20, 40, 50, and 60 mm). Generally, the viscosity measurements among rheometers differed significantly ( P < 0.05 ). For larger geometry diameter (40, 50, and 60 mm) and at lower temperatures (8 °C), viscosity measurements at lower shear rate (0.01, 0.1, and 1.0 s-1 ) were significantly different. Rheometer brand significantly affected storage modulus only at low (0.01%) and high levels (10% and 100%) of strain. Temperature was an influencing factor on viscoelastic behaviors only at high strain (>10%). Storage moduli values obtained by frequency sweeps were not affected by rheometer or plate diameter. Overall, rheometer, geometry, and temperature can influence rheological measurements and care should be taken when comparing data across laboratories or published works. Higher shear rates (≥10 s-1 ) and moderate strains (0.1% to 10%) generally provide more repeatable data among different laboratories. PRACTICAL APPLICATION: This study provides information on what factors may potentially influence rheological measurements conducted across different laboratories. It is useful for rheometer users who want to compare their experimental data to published data or compare two sets of published data. It is better to compare data collected at shear rates 10 s-1 and strains between 0.1% and 1.0%.

Effects of high pressure processing on the physicochemical and microbiological parameters, bioactive compounds, and antioxidant activity of a lemongrass-lime mixed beverage.

This study determined the optimal pressure and time conditions for the high pressure processing (HPP) of a lemongrass-lime mixed beverage. The physicochemical and microbiological characteristics, bioactive compounds, and antioxidant activity of the beverage treated under the optimal HPP conditions were evaluated immediately after processing and during 8 weeks of storage at 4 °C, compared to untreated (control) and thermally pasteurized beverages. HPP at 250 MPa for 1 min at 25 °C ensured microbiological safety, according to inactivation tests with Listeria innocua as the target microorganism, without significant losses of vitamin C and phenolic compounds. Immediately after processing, the HPP treated beverage retained its original bioactive compounds content and showed physicochemical characteristics that were closer to the untreated control compared with the thermally pasteurized beverage. In addition, HPP provided microbiological quality and improved the shelf life of the beverage, demonstrating that it represents a reliable alternative to thermal treatment of lemongrass-lime mixed beverages.

Extraction of bioactive compounds and essential oils from mediterranean herbs by conventional and green innovative techniques: A review.

Market interest in aromatic plants from the Mediterranean is continuously growing mainly due to their medicinal and bioactive compounds (BACs) with other valuable constituents from essential oils (EOs). From ancient times, these plants have been important condiments for traditional Mediterranean cuisine and remedies in folk medicine. Nowadays, they are considered as important factors for food quality and safety, due to prevention of various deteriorative factors like oxidations and microbial spoilage. EOs have different therapeutic benefits (e.g. antioxidant, anti-inflammatory, antimicrobial, and antifungal), while BACs mostly affect nutritive, chemical, microbiological, and sensory quality of foods. Currently, many plant extracts are used for functional (healthy) foods, which additionally fuels consumer and industrial interest in sustainable and non-toxic routes for their production. EO yields from dried plants are below 5%. Their extraction is strongly dependent on the hydrophobic or lipophilic character of target molecules, hence the common use of organic solvents. Similarly, BACs encompass a wide range of substances with varying structures as reflected by their different physical/chemical qualities. Thus, there is a need to identify optimal non-toxic extraction method(s) for isolation/separation of EO/BCs from plants. Various innovative non-thermal extractions (e.g. ultrasound-, high-pressure-, pulsed electric fields assisted extraction, etc.) have been proposed to overcome the above mentioned limitations. These techniques are "green" in concept, as they are shorter, avoid toxic chemicals, and are able to improve extract yields and quality with reduced consumption of energy and solvents. This research provides an overview of such extractions of both BAC and EOs from Mediterranean herbs, sustained by innovative and non-conventional energy sources.

Combined Effect of Ultrasound and Mild Temperatures on the Inactivation of E. coli in Fresh Carrot Juice and Changes on its Physicochemical Characteristics.

The combination of ultrasound and mild temperatures to process fruits and vegetables juices is a novel approach that is showing promising results for microbial inactivation and preservation of bioactive compounds and sensory attributes. This study centers on investigating the inactivation of Escherichia coli (ATCC 11755) in carrot juice as a result of the combined effect of ultrasound (24 kHz frequency, 120 µm, and 400 W) with temperature (50, 54, and 58 °C) and processing time (0 to 10 min). In addition, the possible changes in physicochemical properties and the retention of bioactive compounds after processing were analyzed. Microbial inactivation with ultrasound treatment at 50 °C resulted in 3.5 log reduction after 10 min, whereas at 54 °C almost 5 log reduction was attained in the same period of time; meanwhile, for treatment at 58 °C, no viable cells were detected (>5 log reduction) after 2 min. There was no significant difference (P > 0.05) on pH (6.80 to 6.82), °Brix (8.0 to 8.5), titratable acidity (0.29% to 0.30%), total carotenoid (1774 to 1835 µg/100 mL), phenolic compounds (20.19 to 20.63 µg/mL), ascorbic acid (4.8 mg/100 mL), and color parameters between fresh and ultrasound treated samples at the studied temperatures. To predict the inactivation patterns, observed values were tested using 3 different general models: first-order, Weibull distribution, and biphasic. The Weibull and biphasic models show good correlation for inactivation under all processing conditions. Results show ultrasound in combination with mild temperature could be effectively used to process fresh carrot juice providing a safe product without affecting physicochemical characteristics. PRACTICAL APPLICATIONS: The combination of ultrasound and mild temperatures is effective in reducing microbial load in carrot juice to safe levels. This combination would be beneficial in the industrial processing of carrot juice without altering the quality attributes or bioactive compounds.

Green Pea and Garlic Puree Model Food Development for Thermal Pasteurization Process Quality Evaluation.

Development and selection of model foods is a critical part of microwave thermal process development, simulation validation, and optimization. Previously developed model foods for pasteurization process evaluation utilized Maillard reaction products as the time-temperature integrators, which resulted in similar temperature sensitivity among the models. The aim of this research was to develop additional model foods based on different time-temperature integrators, determine their dielectric properties and color change kinetics, and validate the optimal model food in hot water and microwave-assisted pasteurization processes. Color, quantified using a* value, was selected as the time-temperature indicator for green pea and garlic puree model foods. Results showed 915 MHz microwaves had a greater penetration depth into the green pea model food than the garlic. a* value reaction rates for the green pea model were approximately 4 times slower than in the garlic model food; slower reaction rates were preferred for the application of model food in this study, that is quality evaluation for a target process of 90 °C for 10 min at the cold spot. Pasteurization validation used the green pea model food and results showed that there were quantifiable differences between the color of the unheated control, hot water pasteurization, and microwave-assisted thermal pasteurization system. Both model foods developed in this research could be utilized for quality assessment and optimization of various thermal pasteurization processes.

Headspace oxygen as a hurdle to improve the safety of in-pack pasteurized chilled food during storage at different temperatures.

This study investigated the use of headspace oxygen in a model food system to prevent the growth of anaerobic pathogenic bacteria in in-pack pasteurized food at various storage temperatures. Three model food formulations prepared with tryptic soy broth and three agar concentrations (0.1, 0.4 and 1.0%) were sealed without removing the air from the package in high oxygen barrier pouches (OTR=0.3cm3/m2·day·atm). Important properties influencing bacterial growth, including pH and water activity (aw) were determined. The oxygen sorption kinetics of each model food were obtained at three different storage temperatures (8, 12, and 20°C) using an OxySense Gen III 300 system. An analytical solution of Fick's second law was used to determine the O2 diffusion coefficient. Growth challenge studies at 12 and 20°C were conducted at three selected locations (top, center and bottom layers) in model foods containing 1% agar. Model foods were inoculated with Clostridium sporogenes PA 3679 (300spores/mL), and were classified as low-acid (pH>4.5, aw>0.85). When the storage temperature decreased from 20 to 8°C, the oxygen diffusion decreased from 0.82×10-9m2/s to 0.68×10-9m2/s. As the agar concentration was increased from 0.1 to 1.0%, the effective oxygen permeability decreased significantly (p=0.007) from 0.88×10-9m2/s to 0.65×10-9m2/s. When the inoculated model foods were stored at 12°C for 14days, C. sporogenes PA 3679 was unable to grow. As the storage temperature was increased to 20°C, significant bacterial growth was observed with storage time (p<0.0001), and the C. sporogenes PA 3679 population increased by around 6logCFU/g. However, the location of the food did not influence the growth distribution of C. sporogenes PA 3679. These results demonstrate that oxygen diffusion from the pouch headspace was primarily limited to the food surface. Findings suggest that the air/oxygen present in the package headspace may not be considered as a food safety hurdle in the production of pasteurized packaged food.

Physical and structural changes induced by high pressure on corn starch, rice flour and waxy rice flour.

The impact of high pressure (HP) processing on corn starch, rice flour and waxy rice flour was investigated as a function of pressure level (400MPa; 600MPa), pressure holding time (5min; 10min), and temperature (20°C; 40°C). Samples were pre-conditioned (final moisture level: 40g/100g) before HP treatments. Both the HP treated and the untreated raw materials were evaluated for pasting properties and solvent retention capacity, and investigated by differential scanning calorimetry, X-ray diffractometry and environmental scanning electron microscopy. Different pasting behaviors and solvent retention capacities were evidenced according to the applied pressure. Corn starch presented a slower gelatinization trend when treated at 600MPa. Corn starch and rice flour treated at 600MPa showed a higher retention capacity of carbonate and lactic acid solvents, respectively. Differential scanning calorimetry and environmental scanning electron microscopy investigations highlighted that HP affected the starch structure of rice flour and corn starch. Few variations were evidenced in waxy rice flour. These results can assist in advancing the HP processing knowledge, as the possibility to successfully process raw samples in a very high sample-to-water concentration level was evidenced. INDUSTRIAL RELEVANCE: This work investigates the effect of high pressure as a potential technique to modify the processing characteristics of starchy materials without using high temperature. In this case the starches were processed in the powder form - and not as a slurry as in previously reported studies - showing the flexibility of the HP treatment. The relevance for industrial application is the possibility to change the structure of flour starches, and thus modifying the processability of the mentioned products.

Effect of starch-beeswax coatings on quality parameters of blackberries (Rubus spp.).

There is increased interest in berry fruits due to health benefits, and maintenance of fruit quality for longer periods of time has been a priority. We previously found that starch based coatings applied on raspberries was associated to volatile compounds production due to anoxic conditions. The objective of this work was to design more hydrophobic coatings with reduced thickness. A starch-beeswax dispersion containing 2 % (w/v) modified tapioca starch added with either 0.5 or 1.0 % (w/v) beeswax microparticles was produced, and used for spray coating freshly harvested blackberries (Rubus spp.). Coatings were air dried, packed in plastic trays and stored up to 16 days at 4 °C and 88 % relative humidity. Storage quality parameters such as hardness, respiration rate, anthocyanins content, total phenols, color changes and weight loss were evaluated. We did not find Interactions among coating ingredients, and incorporation of beeswax reduced moisture transfer rate. Coatings did not occlude the stomata and apparently did not over-hydrate the cuticle. This characteristic allowed appropriate gas exchange (O2 and CO2), and reduced accumulation of volatile compounds associated to fermentative metabolism. Respiration rates were 4.207 ± 0.157, 4.557 ± 0.220 and 4.780 ± 0.050 mmol CO2 kg(-1) h(-1) for control, 0.5 and 1 % of wax content in coatings, respectively. However, ethylene production increased throughout storage time along with beeswax concentration, indicating stressful conditions for the fruit. This trend appears to be related with changes in total phenols and anthocyanins during storage. Edible coatings based on starch and hydrophobic particles should be reformulated to maintain quality of stored berry fruits.

Physico-chemical parameters, bioactive compounds and microbial quality of thermo-sonicated carrot juice during storage.

Thermosonication has been successfully tested in food for microbial inactivation; however, changes in bioactive compounds and shelf-life of treated products have not been thoroughly investigated. Carrot juice was thermo-sonicated (24 kHz, 120 µm amplitude) at 50 °C, 54 °C and 58 °C for 10 min (acoustic power 2204.40, 2155.72, 2181.68 mW/mL, respectively). Quality parameters and microbial growth were evaluated after processing and during storage at 4 °C. Control and sonicated treatments at 50 °C and 54 °C had 10, 12 and 14 d of shelf-life, respectively. Samples sonicated at 58 °C had the best quality; microbial growth remained low at around 3-log for mesophiles, 4.5-log for yeasts and molds and 2-log for enterobacteria after 20 d of storage. Furthermore, thermo-sonicated juice at 58 °C retained >98% of carotenoids and 100% of ascorbic acid. Phenolic compounds increased in all stored, treated juices. Thermo-sonication is therefore a promising technology for preserving the quality of carrot juice by minimising the physicochemical changes during storage, retarding microbial growth and retaining the bioactive compounds.

Advanced retorting, microwave assisted thermal sterilization (MATS), and pressure assisted thermal sterilization (PATS) to process meat products.

Conventional thermal processes have been very reliable in offering safe sterilized meat products, but some of those products are of questionable overall quality. Flavor, aroma, and texture, among other attributes, are significantly affected during such processes. To improve those quality attributes, alternative approaches to sterilizing meat and meat products have been explored in the last few years. Most of the new strategies for sterilizing meat products rely on using thermal approaches, but in a more efficient way than in conventional methods. Some of these emerging technologies have proven to be reliable and have been formally approved by regulatory agencies such as the FDA. Additional work needs to be done in order for these technologies to be fully adopted by the food industry and to optimize their use. Some of these emerging technologies for sterilizing meat include pressure assisted thermal sterilization (PATS), microwaves, and advanced retorting. This review deals with fundamental and applied aspects of these new and very promising approaches to sterilization of meat products.

Separation of suspensions and emulsions via ultrasonic standing waves - a review.

Ultrasonic standing waves (USW) separation is an established technology for micro scale applications due to the excellent control to manipulate particles acoustically achieved when combining high frequency ultrasound with laminar flow in microchannels, allowing the development of numerous applications. Larger scale systems (pilot to industrial) are emerging; however, scaling up such processes are technologically very challenging. This paper reviews the physical principles that govern acoustic particle/droplet separation and the mathematical modeling techniques developed to understand, predict, and design acoustic separation processes. A further focus in this review is on acoustic streaming, which represents one of the major challenges in scaling up USW separation processes. The manuscript concludes by providing a brief overview of the state of the art of the technology applied in large scale systems with potential applications in the dairy and oil industries.

Milk processed by pulsed electric fields: evaluation of microbial quality, physicochemical characteristics, and selected nutrients at different storage conditions.

UNLABELLED: Pulsed electric fields (PEF) technology was used to pasteurize raw milk under selected treatments. Processing conditions were: temperature 20, 30, and 40 °C, electric field 30.76 to 53.84 kV/cm, and pulse numbers 12, 24, and 30 for skim milk (SM), and 12, 21, and 30 for whole milk (WM) (2 µs pulse width, monopolar). Physicochemical parameters (pH, electrical conductivity, density, color, solids nonfat [SNF]) and composition (protein and fat content) were measured after processing. Shelf life of SM and WM was assessed after processing at 46.15 kV/cm, combined with temperature (20 to 60 °C) and 30 pulses. Mesophilic and psychrophilic loads and pH were evaluated during storage at 4 and 21 °C. Results showed minor variations in physicochemical properties after processing. There was an interesting trend in SM in SNF, which decreased as treatment became stronger; similar behavior was observed for fat and protein, showing a 0.18% and 0.17% decrease, respectively, under the strongest conditions. Protein and fat content decreased in WM samples treated at 40 °C, showing a decrease in protein (0.11%), and an even higher decrease in fat content. During storage, PEF-treated milk samples showed higher stability at 4 °C with minor variations in pH; after 33 d, pH was higher than 6. However samples at 21 °C showed faster spoilage and pH dropped to 4 after 5 d. Growth of mesophilic bacteria was delayed in both milks after PEF processing, showing a 6- and 7-log cycles for SM and WM, respectively, after day 25 (4 °C); however, psychrophilic bacteria grew faster in both cases. PRACTICAL APPLICATION: Pulsed electric fields (PEF) technology in the pasteurization of liquid food products has shown positive results. Processing times can be reduced considerably, which in turn reduces the loss of nutrients and offers important savings in energy. PEF has been used successfully to pasteurize some liquid foods, but it is still not used commercially in milk pasteurization, although several trials have shown the positive effects of PEF milk pasteurization, which could allow for its future use at the industrial level.

Development and characterization of edible films based on mucilage of Opuntia ficus-indica (L.).

Mucilage of Opuntia ficus-indica (OFI) was extracted and characterized by its composition and molecular weight distribution. Mucilage film-forming dispersions were prepared under different pHs (3, 4, 5.6, 7, and 8) and calcium concentration (0% and 30% of CaCl(2), with respect to mucilage's weight), and their particle size determined. Mucilage films with and without calcium (MFCa and MF, respectively) were prepared. The effect of calcium and pH on mucilage films was evaluated determining thickness, color, water vapor permeability (WVP), tensile strength (TS), and percentage of elongation (%E). The average molecular weight of the different fractions of mucilage was: 3.4 x 10(6) (0.73%), 1 x 10(5) (1.46%), 1.1 x 10(3) (45.79%), and 2.4 x 10(2) Da (52.03%). Aqueous mucilage dispersions with no calcium presented particles with an average size d(0.5) of 15.4 microm, greater than the dispersions with calcium, 13.2 microm. MFCa films showed more thickness (0.13 mm) than the MF films (0.10 mm). The addition of calcium increased the WVP of the films from 109.94 to 130.45 gmm/m(2)dkPa. Calcium and pH affected the mechanical properties of the films; the largest TS was observed on MF films, whereas the highest %E was observed on MFCa films. The highest differences among MF and MFCa films were observed at pHs 5.6 and 7 for TS and at pHs 4 and 8 for %E. No effect of pH and calcium was observed on luminosity and hue angle. Chroma values were higher for MF when compared with MFCa, and increased as pH of the films increased. Practical Application: In this study mucilage from nopal was extracted and characterized by its ability to form edible films under different pHs, and with or without the addition of calcium. Opuntia ficus-indica mucilage had the ability to form edible films. In general, it can be considered that mucilage films without modification of pH and without the addition of calcium have the best water vapor barrier properties and tensile strength. Mucilage from nopal could represent a good option for the development of edible films in countries where nopal is highly produced at low cost, constituting a processing alternative for nopal.

Processing of soft Hispanic cheese ("queso fresco") using thermo-sonicated milk: a study of physicochemical characteristics and storage life.

Queso fresco is a handmade cheese consumed in Latin America and some regions of the United States. However, deficient milk processing has affected its microbial quality and it has an extremely short shelf life and low yield. The objective of this work was to process queso fresco using thermo-sonicated milk; physicochemical parameters were evaluated, including microbial quality during storage (4 °C). An ultrasonic processor (UP400S, 400 W, 24 kHz, 120 µm) was used to sonicate raw milk. Seven milk systems (500 mL each) were evaluated: 1 untreated, and 6 treated at 63 °C/30 min; 63 °C/10 min + sonication; 63 °C/30 min + sonication; 72 °C/15 s; 72 °C/15 s + sonication; and 72 °C/1 min + sonication. A conventional cheese-making process was followed for all systems. The effect of sonication on milk was quite noticeable. Curdling times were reduced considerably, cheese yield (20.6%) was almost doubled, and luminosity of cheese was increased (L*). Textural properties and microstructure images matched very well. Queso fresco processed at 63 °C/120 µm/30 min had the best quality. After storage for 23 d at 4 °C mesophilic count was just 4 log; psychrophilic count, 3.5 log; and enterobacteria count, 3 log. The pH and color remained almost constant and a minor degree of syneresis was observed at end of storage. Due to microstructural rearrangement of the milk components such as fat globules and casein micelles, cheese yield was doubled compared to the traditional handmade product. Shelf life was extended considerably and the product had higher quality.

Feeding the World Today and Tomorrow: The Importance of Food Science and Technology: An IFT Scientific Review.

by Philip E. Nelson, 2007 World Food Prize Laureate; Professor Emeritus, Food Science Dept., Purdue Univ. Just as society has evolved over time, our food system has also evolved over centuries into a global system of immense size and complexity. The commitment of food science and technology professionals to advancing the science of food, ensuring a safe and abundant food supply, and contributing to healthier people everywhere is integral to that evolution. Food scientists and technologists are versatile, interdisciplinary, and collaborative practitioners in a profession at the crossroads of scientific and technological developments. As the food system has drastically changed, from one centered around family food production on individual farms and home food preservation to the modern system of today, most people are not connected to their food nor are they familiar with agricultural production and food manufacturing designed for better food safety and quality. The Institute of Food Technologists-a nonprofit scientific society of individual members engaged in food science, food technology, and related professions in industry, academia, and government-has the mission to advance the science of food and the long-range vision to ensure a safe and abundant food supply contributing to healthier people everywhere. IFT convened a task force and called on contributing authors to develop this scientific review to inform the general public about the importance and benefits of food science and technology in IFT's efforts to feed a growing world. The main objective of this review is to serve as a foundational resource for public outreach and education and to address misperceptions and misinformation about processed foods. The intended audience includes those who desire to know more about the application of science and technology to meet society's food needs and those involved in public education and outreach. It is IFT's hope that the reader will gain a better understanding of the goals or purposes for various applications of science and technology in the food system, and an appreciation for the complexity of the modern food supply. Abstract: This Institute of Food Technologists scientific review describes the scientific and technological achievements that made possible the modern production-to-consumption food system capable of feeding nearly 7 billion people, and it also discusses the promising potential of ongoing technological advancements to enhance the food supply even further and to increase the health and wellness of the growing global population. This review begins with a historical perspective that summarizes the parallel developments of agriculture and food technology, from the beginnings of modern society to the present. A section on food manufacturing explains why food is processed and details various food processing methods that ensure food safety and preserve the quality of products. A section about potential solutions to future challenges briefly discusses ways in which scientists, the food industry, and policy makers are striving to improve the food supply for a healthier population and feed the future. Applications of science and technology within the food system have allowed production of foods in adequate quantities to meet the needs of society, as it has evolved. Today, our production-to-consumption food system is complex, and our food is largely safe, tasty, nutritious, abundant, diverse, convenient, and less costly and more readily accessible than ever before. Scientific and technological advancements must be accelerated and applied in developed and developing nations alike, if we are to feed a growing world population.

Food powders flowability characterization: theory, methods, and applications.

Characterization of food powders flowability is required for predicting powder flow from hoppers in small-scale systems such as vending machines or at the industrial scale from storage silos or bins dispensing into powder mixing systems or packaging machines. This review covers conventional and new methods used to measure flowability in food powders. The method developed by Jenike (1964) for determining hopper outlet diameter and hopper angle has become a standard for the design of bins and is regarded as a standard method to characterize flowability. Moreover, there are a number of shear cells that can be used to determine failure properties defined by Jenike's theory. Other classic methods (compression, angle of repose) and nonconventional methods (Hall flowmeter, Johanson Indicizer, Hosokawa powder tester, tensile strength tester, powder rheometer), used mainly for the characterization of food powder cohesiveness, are described. The effect of some factors preventing flow, such as water content, temperature, time consolidation, particle composition and size distribution, is summarized for the characterization of specific food powders with conventional and other methods. Whereas time-consuming standard methods established for hopper design provide flow properties, there is yet little comparative evidence demonstrating that other rapid methods may provide similar flow prediction.