A new active packaging system based on chickpea-based edible coatings added with microcapsules of Cosmos sulphureus Cav. flower extract.

BACKGROUND: The Cosmos sulphureus Cav. plant is studied for its high polyphenolic content with antioxidant properties. Its flowers, rich in phenolic acids, flavonoids, and tannins, hold promise as antioxidants in food preservation. The inclusion of these compounds in chickpea-based coatings with a previously studied preservative effect would be an excellent option as a food preservation method and microencapsulation addresses challenges like dispersion and degradation of polyphenols in the coating. The objective of this research was to evaluate the in vitro antioxidant activity of Cosmos sulphureus leaves, seed, and flower extracts and explore the protective effects of chickpea-based coatings containing microcapsules of flower polyphenolic extract on the chemical quality of stored roasted sunflower seeds during storage. RESULTS: The ethanolic leaf extract exhibited the highest antiradical activity, followed by the aqueous flower extract. After a storage period of 15 days, at 40 °C, the chickpea-based coatings effectively delayed lipid oxidation in the roasted sunflowers seeds, and the inclusion of polyphenolic microcapsules with 0.01% extract (SMC 0.01%) in the coating significantly improved the protective effect. By day 15 of storage, SMC 0.01% showed comparable peroxide value, conjugated dienes, and linoleic acid content to samples containing the synthetic antioxidant BHT (butylated hydroxytoluene). Samples that only contained chickpea-based coating and coating with polyphenolic microcapsules with 0.005% extract exhibited significantly greater reduction in fatty acid content compared to the 0.01% SMC treatment. CONCLUSION: The chickpea-based coating with polyphenolic microcapsules demonstrated antioxidant activity akin to synthetic BHT, offering a promising biopackaging solution for lipid-rich foods like roasted sunflower seeds. © 2024 Society of Chemical Industry.

Effects of solar tunnel drying, shade drying and microwave drying methods on the drying kinetics of strawberry (Fragaria ananassa) / Efeitos dos métodos de secagem em túnel solar, secagem à sombra e secagem por microondas na cinética de secagem de morango (Fragaria ananassa)

Whole and halved strawberries were dried by using three methods, which were solar tunnel drying, shade drying, and microwave drying (180W, 540W, and 900W) to determine drying characteristic and modelling. The researchers measured solar irradiation at ambient and drying air temperatures and air velocity at specific intervals in various parts of the dryer. How microwave drying (180, 540, and 900 W) affected the drying time and drying ratio of the whole and halved strawberry samples was investigated. In addition, the data on the drying process were applied to 5 different mathematical models, which were Weibull distribution, Midilli et al., Jena and Das and Aghbashlo et al. Equation Models. The researchers compared the performance levels of the models according to correlation coefficient (R2), chi-square value (χ2), besides the root mean square error (RMSE) between moisture ratios that were observed and predicted. Furthermore, the Weibull Distribution and Midilli et al. models were found to reveal the ratio of drying in a satisfactory way for all the methods of drying.(AU)

Morangos inteiros e cortados ao meio foram secos usando três métodos, que foram secagem em túnel solar, secagem à sombra e secagem por micro-ondas (180W, 540W e 900W) para determinar a característica de secagem e modelagem. Os pesquisadores mediram a irradiação solar nas temperaturas ambiente e de secagem do ar e a velocidade do ar em intervalos específicos em várias partes do secador. Como a secagem por micro-ondas (180, 540 e 900 W) afetou o tempo de secagem e a proporção de secagem das amostras inteiras e cortadas de morango foi investigado. Além disso, os dados do processo de secagem foram aplicados a 5 modelos matemáticos diferentes, que foram a distribuição de Weibull, Midilli et al., Jena e Das e Aghbashlo et al. Modelos de equação. Os pesquisadores compararam os níveis de desempenho dos modelos de acordo com o coeficiente de correlação (R2), valor do qui-quadrado (χ2), além da raiz do erro quadrático médio (RMSE) entre as razões de umidade observadas e previstas. Além disso, a Distribuição Weibull e Midilli et al. os modelos revelaram a proporção de secagem de forma satisfatória para todos os métodos de secagem.(AU)

Effect of calcium hydroxide mixed with preservatives on physicochemical characteristics and sensory shelf-life of corn tortilla.

BACKGROUND: The objective of the study was to evaluate the physicochemical characteristics and shelf-life of corn tortilla stored at room temperature (25 °C) using aw modifiers (propylene glycol and glycerol) and pH modifiers (fumaric acid and sodium benzoate) as preservatives combined with calcium hydroxide. Detection thresholds were used to determine the maximum preservative concentration and calcium hydroxide. Physicochemical characterization and sensory evaluation were used to determine the stability and sensory shelf-life of tortillas. RESULTS: Control, calcium hydroxide, calcium hydroxide + fumaric acid, calcium hydroxide + glycerol, calcium hydroxide + propylene glycol, and calcium hydroxide + sodium benzoate treatments had rounded half-lives of 1, 2, 1, 2, 2, and 2 days respectively. Glycerol combined with calcium hydroxide resulted in tortillas with lower pH variations over time. Mold presence was the critical attribute causing tortilla rejection. CONCLUSION: The use of aw modifiers had a better effect in preserving corn tortilla, as the concentration of pH modifiers at detection threshold levels was not able to reach an optimum performance when combined with calcium hydroxide. © 2021 Society of Chemical Industry.

Mechanical properties of lettuce (Lactuca sativa L. ) for horticultural machinery design

Currently, there is a growing need to develop machines that replace human work efficiently and effectively in horticulture with the same sensibility of the human hand, since horticultural foods are notably very fragile to handle and process, especially considering machinery and systems. This work aimed to determine the mechanical properties of lettuce (Lactuca sativa L.) variety Crispa. For that, two methodologies were used in the field of material engineering: one specific for polymers and composites - the standard ASTM D3039 - Standard test method for tensile properties of polymer matrix composite materials (ASTM, 2002a) and the other specific for plastic films - the ASTM 882 - Standard test method for tensile properties of thin plastic sheeting (ASTM, 2002b). The tests were adapted for lettuce samples. The mechanical properties for the leaf and stem of head lettuce (var. Crispa) were obtained with appropriate statistical rigor, which can be considered valid initial estimates for dimensioning mechanisms and systems of machines for horticultural works specialized in lettuce. These properties provide fundamental engineering parameters to design machine elements that interact with biological materials, allowing to develop devices that generate minor damage to biological structures in lettuce.

Effect of drying methods on drying kinetics, energy features, thermophysical and microstructural properties of Stevia rebaudiana leaves.

BACKGROUND: Stevia leaves were subjected to convective hot-air, infrared and vacuum drying at 40, 60 and 80 °C, followed by an assessment of thermophysical properties and microstructure, along with drying kinetics modelling and evaluation of energy features for all drying operations. RESULTS: Effective moisture diffusivity (Deff ) showed dependency on temperature with values ranging from 1.08 × 10-12 to 7.43 × 10-12  m2  s-1 for convective drying, from 0.71 × 10-12 to 6.60 × 10-12  m2  s-1 for infrared drying, and from 1.29 × 10-12 to 5.39 × 10-12  m2  s-1 for vacuum drying. The thermal properties of the dried Stevia leaves under different drying conditions showed values of density, specific heat, thermal diffusivity, thermal conductivity and thermal effusivity ranging from 95.6 to 116.2 kg m-3 , 3050 to 3900 J kg-1  K-1 , 4.28 × 10-7 to 5.60 × 10-7  m2  s-1 , 0.16 to 0.23 W m-1  K-1 and 244 to 305 W s0.5  m-2  K-1 , respectively. As for microstructure, convective hot-air drying showed better preserved leaf characteristics, compared to infrared- and vacuum-drying, whereby scanning electron microscopy (SEM) image analysis also revealed noticeable differences at higher temperatures. Statistical analysis showed that the Midilli-Kuçuk model fitted best the experimental data of drying curves (0.961 < r2 < 0.999, 0.000064 < SSE < 0.005359, and 0.000074 < χ2 < 0.006278). Comparison of the drying methods with respect to energy features showed that convective drying at 80 °C led to lowest specific energy consumption (61.86 kW h kg-1 ) with highest efficiency (8.5%). CONCLUSION: The results of this study contribute to a better understanding of the drying behaviour and showed that thermophysical properties of dried Stevia leaves and energy features are affected by drying methods. © 2021 Society of Chemical Industry.

Ohmic heating increases inactivation and morphological changes of Salmonella sp. and the formation of bioactive compounds in infant formula.

The effect of ohmic heating (OH) (50, 55, and 60 °C, 6 V/cm) on the inactivation kinetics (Weibull model) and morphological changes (scanning electron microscopy and flow cytometry) of Salmonella spp. in infant formula (IF) was evaluated. In addition, thermal load indicators (hydroxymethylfurfural and whey protein nitrogen index, HMF, and WPNI) and bioactive compounds (DPPH, total phenolics, ACE, α-amylase, and α-glucosidase inhibitory activities) were also studied. OH presented a more intense inactivation rate than conventional heating, resulting in a reduction of about 5 log CFU per mL at 60 °C in only 2.91 min, being also noted a greater cell membrane deformation, higher formation of bioactive compounds, and lower values for the thermal load parameters. Overall, OH contributed to retaining the nutritional value and improve food safety in IF processing.

Bioprotective extracts from Lactobacillus acidophilus CRL641 and Latilactobacillus curvatus CRL705 inhibit a spoilage exopolysaccharide producer in a refrigerated meat system.

The effect of bioprotective extracts (BEs) from Latilactobacillus curvatus CRL705 and Lactobacillus acidophilus CRL641 against Latilactobacillus sakei CRL1407 was evaluated in a refrigerated meat model system under vacuum and aerobic conditions at 4 and 10 °C. As shown by culturing, the BE-1 from L. acidophilus completely inhibited the spoilage strain, while that from Lat. Curvatus CRL705 (BE-2) and its combination with BE-1 exerted a bacteriostatic effect. The antimicrobial activity and exopolysaccharide production correlated with the efficacy of inhibitory treatment while final pH decrease was higher in control samples. When flow cytometry was applied, a lack of correlation with plate counting was found; counts under the detection limit for BE-1 at 21 and 28 days at 4 and 10 °C represented between 64.15 and 73.70% of dead cells. Thus, the concurrence of lactic acid bacteria as biocontrol agents and the use of more accurate tools to prevent the growth of deteriorating species will contribute to the extension of fresh meat shelf-life without quality loss.

Effects of combined application of high-pressure processing and active coatings on phenolic compounds and microbiological and physicochemical quality of apple cubes.

BACKGROUND: In recent years the use of high-pressure processing (HPP) of fruit products has steadily increased due to its antimicrobial effectiveness and the retention of nutritional and quality attributes compared to conventional thermal technologies. Edible coatings are already being used to enhance the quality of minimally processed fruits. Thus, apple cubes (AC) and alginate-vanillin-coated apple cubes (AVAC) were subjected to HPP (400 MPa/5 min/35 °C). The microbiological and physicochemical parameters were evaluated and the bioactive compounds were monitored before and after HPP of apple cubes. Also, an in vitro gastrointestinal digestion (GID) was conducted. RESULTS: HPP left L. monocytogenes counts below the detection limit (2 log UFC g-1 ), regardless of the presence of coating. For E. coli, HPP + active coating showed a synergism affording the greatest reduction (>5 log) for AVAC-HPP. Firmness was maintained in AVAC-HPP samples, while AC-HPP samples suffered reductions of 35%. Colour attributes were also better retained in AVAC-HPP samples. In general, HPP led to a decrease in phenolic compounds. Regarding the effects of GID, vanillin-based active coating exerted a protective effect on some phenolics. Thus, p-coumaroylquinic acid concentration was maintained for AVAC and AVAC-HPP during GID. Epigallocatechin, the compound with the highest concentration in apple cubes, increased for AVAC (106%) and AVAC-HPP (57%). Also, phloridzin concentration increased for AVAC-HPP (17%). At the end of GID, procyanidin B1 and epigallocatechin were the main phenolic compounds for all samples, AVAC showing the highest concentration. CONCLUSIONS: This work demonstrates that the combined application of HPP and active coatings on apple cubes could be used to obtain a safe and good-quality product. © 2021 Society of Chemical Industry.

Physicochemical treatments for the reduction of aflatoxins and Aspergillus niger in corn grains (Zea mays).

BACKGROUND: Corn grains are commonly contaminated with mycotoxins and fungi. The purpose of this study was to evaluate the reduction of aflatoxins B1 , B2 , G1 , and G2 and the inhibition of Aspergillus niger in corn grains using ultrasound, ultraviolet (UV) radiation, electrolyzed water, and sodium bicarbonate. The determination of aflatoxins was performed by high-performance liquid chromatography with fluorescence detection and postcolumn derivatization, and analysis of A. niger was performed by evaluating mycelial growth in potato dextrose agar. The best treatment for reducing aflatoxins and inhibiting mycelial growth was evaluated in corn contaminated with A. niger. RESULTS: The results show a significant reduction in aflatoxins in the following order: sodium bicarbonate > ultrasound > UV > electrolyzed water for aflatoxins B1 , B2 , and G2 . For aflatoxin G1 , the order of reduction was sodium bicarbonate > ultrasound > electrolyzed water > UV, with maximum values between 70.50% and 87.03% reached with sodium bicarbonate; for the other treatments, the reduction was between 51.51% and 65.44%. Regarding the fungus, the order of inhibition in the control of mycelial growth was sodium bicarbonate > ultrasound > electrolyzed water > UV in corn grains, and inhibition of mycelial growth was obtained at a sodium bicarbonate concentration of 3.0 g L-1 . CONCLUSION: Sodium bicarbonate, electrolyzed water, ultrasound, and UV radiation inhibited the growth of A. niger on potato dextrose agar and reduced the contents of aflatoxins B1 , B2 , G1 , and G2 in vitro. Sodium bicarbonate showed an ability to inhibit mycelial growth in corn grains. © 2020 Society of Chemical Industry.

Proximate composition and kinectics drying of sweet pine nuts compared to typical nuts of Araucaria angustifolia / Composição proximal e cinética de secagem de pinhões doces e pinhões típicos de Araucaria angustifolia

The objective of this research was to determine the proximate composition and kinetics drying of sweet pine nuts compared to typical pine nuts of Araucaria angustifolia. This study is based on the proximate components, color, and duration of pine nuts drying of both types, and the influence of temperature and cutting geometry on the dehydration process. Sweet pine nuts had lower calorific value and carbohydrate content, but higher lipid, dietary fiber, protein, and ash contents when compared to typical pine nuts. Color of sweet pine nuts is light pink whereas the typical pine nut is yellowish-white. Sweet pine nuts were also softer. Drying kinetics of the seeds fit well into the logistic and Thompson models. To accelerate drying rates, we recommend slicing pine nuts into thin cross-sections and drying them at temperatures of 60 °C for typical pine nuts and 70 °C for sweet pine nuts.(AU)

O objetivo deste trabalho foi determinar a composição centesimal e a cinética de secagem de pinhões doces em comparação com pinhões típicos de Araucaria angustifolia. Este estudo baseia-se na composição centesimal, cor e duração da secagem dos pinhões de ambos os tipos e na influência da temperatura e da geometria de corte no processo de desidratação. Os pinhões doces apresentaram menor valor calorífico e conteúdo de carboidratos. Por outro lado, apresentaram maior teor de lipídios, fibras alimentares, proteínas e cinzas quando comparados aos pinhões típicos. A cor dos pinhões doces é rosa claro, enquanto o pinhão típico é branco amarelado. Os pinhões doces também são mais macios. A cinética de secagem das sementes se enquadra bem nos modelos logístico e de Thompson. Para acelerar as taxas de secagem, recomendamos fatiar os pinhões em seções finas e secá-los a temperaturas de 60 °C para pinhões típicos e 70 °C para pinhões doces.(AU)

Effect of ethanol pretreatment on melon convective drying.

The aim of this study was to evaluate the effectiveness of the use of ethanol, ultrasound and/or vacuum as a pretreatment to melon drying. Eight types of pretreatments were performed in which samples were immersed in ethanol solutions with different concentrations (50% and 100%) using four treatment conditions: immersion, immersion with ultrasound (US), with vacuum (VC) and with ultrasound and vacuum (USVC). Drying was performed at 60 °C and five different semi-theoretical drying mathematical models were examined to characterize the drying curves, and quality analyses were carried out. The condition that obtained the lower drying time was using the US pretreatment in 100% ethanol solution. Drying caused a diminution of bioactive compounds and influenced color parameters. However, the samples immersed in 50% ethanol solution and dried obtained minor losses of total phenolics, total carotenoids, and ascorbic acid contents.

Thermal treatment and modified atmosphere packaging delay chilling injury and preserve the quality of cactus stems (Opuntia ficus-indica Mill.) cv Atlixco.

Response surface methodology was applied in order to select the optimal thermal treatment (TT) and modified atmosphere packaging (MAP) needed to preserve minimally processed cactus stems, cv Atlixco. Accordingly, a 42 s/48°C TT together with a 10% CO2 MAP were selected, and their effects evaluated during storage at 4°C. Controls lost more weight (3.8%) than TT (3.3%), MAP (1.4%), and TT-MAP (1.3%) cactus stems. Chilling injury (CI) symptoms decreased and were of a similar magnitude in both MAP and TT-MAP cactus stems, whereas TT-MAP cladodes were better able to preserve their characteristic green color and freshness, even after 28 days. Biochemically, no differences were detected in the electrolyte leakage (EL) of cactus stems, regardless of treatment. However, the high levels of adenosine triphosphate and of the reduced form of ascorbic acid, especially in MAP and TT-MAP cladodes, suggest that an efficient antioxidant system was present in their tissues throughout storage. PRACTICAL APPLICATIONS: In Mexico, cactus stems have been eaten as vegetables since pre-Hispanic times, and their current status as functional foods has helped them spread to various other countries. As cactus stems possess abundant spines, minimal processing is necessary in order to remove them. Stems must also be kept at 4°C so that their quality and general safety as food items are adequately preserved. However, we previously found that this temperature caused significant CI after just 14 days of storage. The present study, therefore, describes the selection of optimal conditions for the application of a TT that, together with a modified atmosphere (MA), induce tolerance to CI and maintain the quality of stems for up to 28 days. As a result, this work provides the necessary postharvest tools to further expand the distribution and sale of minimally processed cactus stems into domestic and international markets.

Synergistic effect of ultraviolet radiation and high hydrostatic pressure on texture, color, and oxidative stability of refrigerated tilapia fillets.

BACKGROUND: The isolated application of high hydrostatic pressure (HHP) and ultraviolet-C (UV-C) radiation may induce physicochemical changes, thus jeopardizing fish quality attributes during refrigerated storage, which could be minimized by the use of synergistic treatments. Therefore, this study investigated the combined effect of UV-C at 0.103 ± 0.002 J cm−2 and HHP at 220 MPa for 10 min on quality parameters of tilapia fillets stored at 4 °C for 15 days. RESULTS: HHP and UV-C+HHP showed higher myoglobin concentration, higher metmyoglobin-reducing activity, and lower a* than control and the UV-C treatment (P < 0.05), reaching 2.49, 2.58, 1.62, 1.54 mg myoglobin g−1 , 13.30, 13.81, 2.29, 2.29%, and 2.32, 2.58, 4.29, 3.98 respectively on the last day of storage. UV-C, HHP, and UV-C+HHP increased water-holding capacity and decreased the pH levels, hardness, and chewiness (P < 0.05). HHP retarded lipid oxidation and UV-C increased protein oxidation compared with control (P < 0.05), achieving 0.81 and 2.80 mg malondialdehyde per kilogram of fish tissue, and 5.50 and 4.15 nmol carbonyl per milligram of protein respectively on 15th day of the storage. CONCLUSION: Both technologies (alone or together) enhanced texture parameters and water-holding capacity. UV-C did not induce color changes and lipid oxidation, whereas HHP showed high potential to prevent meat discoloration, lipid oxidation, and protein oxidation. In addition, this combination of methods could be an alternative to prevent protein oxidation induced by UV-C.

Microencapsulated food-grade antioxidant applied as a preservative of peanut seed quality in microcosm- and pilot-scale trials.

BACKGROUND: In Argentina, peanuts are stored for 3-6 months. It is important to avoid proliferation of fungi and insect pests during this period. In this study, the potential of butylated hydroxyanisole (BHA) microcapsules to conserve peanut kernels was evaluated in microcosms and on a pilot scale. RESULTS: In microcosm assays, microcapsules containing BHA at a dose of 1802 µg g-1 reduced 37% of total fungal count. Higher reductions (77-100%) were obtained with a combined treatment with BHA formulation (1802 µg g-1 ) plus fungicide (methyl thiophanate 0.0100 g L-1  and metalaxyl 0.0133 g L-1 ). However, germination levels of peanut seeds treated with the BHA formulation were less than 6% throughout the incubation time. In pilot-scale trials, the storage conditions allowed the control of fungal development and insect proliferation. Quantifiable levels of BHA were also detected throughout the entire storage period. The combined treatment significantly reduced fungal contamination at 2 months of storage (C1-2015: 37.41%; C1-2016: 28.48%; C2-2016: 45.02%). Seed germination of unshelled stored peanuts was not affected by the formulation. CONCLUSION: The application of the BHA formulation during storage combined with pre-seeding treatment could be an appropriate strategy to maintain the quality of the peanut kernels destined for seed. © 2018 Society of Chemical Industry.

Use of microbial models to evaluate the effect of UV-C light and trans-cinnamaldehyde on the native microbial load of grapefruit (Citrus × paradisi) juice.

The aim of this research was to evaluate the storage stability (5 °C), and microbial modeling, of Rubi red grapefruit (Citrus × paradisi) juice treated with ultraviolet-C (UV-C) light (0, 10 and 20 min), alone or in combination with trans-cinnamaldehyde (trans-CAH) (0, 25 and 50 µg/mL). A 32 factorial design was used and data modeled with the Weibull, Modified Gompertz and Logistic models. A response surface model was used to evaluate the effect of modeling parameters for suggesting the optimum treatment conditions. Treated and some untreated juice lasted up to 9 days without physicochemical and microbial changes. At the higher combination of UV-C light and trans-CAH, the microbial load of grapefruit juice was maintained below 100 CFU/mL up to 15 days. For mesophiles, the three predictive models indicated that the parameters n and Nmax decreased and the parameters λ and tc increased as the combination of UV-C light and trans-CAH increased. The response surface modeling of the parameters obtained by the predictive models showed acceptable correlation for mesophiles (R2 = 0.815-0.977) but not for yeasts (R2 = 0.618-0.815). The three predictive models showed that, the concentration of trans-CAH had more effect on stopping the microbial growth than the UV-C light treatment.

Effects of hurdle technology on Monascus ruber growth in green table olives: a response surface methodology approach

ABSTRACT An ascomycetes fungus was isolated from brine storage of green olives of the Arauco cultivar imported from Argentina and identified as Monascus ruber. The combined effects of different concentrations of sodium chloride (3.5-5.5%), sodium benzoate (0-0.1%), potassium sorbate (0-0.05%) and temperature (30-40 °C) were investigated on the growth of M. ruber in the brine of stored table olives using a response surface methodology. A full 24 factorial design with three central points was first used in order to screen for the important factors (significant and marginally significant factors) and then a Face-Centered Central Composite Design was applied. Both preservatives prevented fungal spoilage, but potassium sorbate was the most efficient to control the fungi growth. The combined use of these preservatives did not show a synergistic effect. The results showed that the use of these salts may not be sufficient to prevent fungal spoilage and the greatest fungal growth was recorded at 30 °C.

Effects of hurdle technology on Monascus ruber growth in green table olives: a response surface methodology approach.

An ascomycetes fungus was isolated from brine storage of green olives of the Arauco cultivar imported from Argentina and identified as Monascus ruber. The combined effects of different concentrations of sodium chloride (3.5-5.5%), sodium benzoate (0-0.1%), potassium sorbate (0-0.05%) and temperature (30-40°C) were investigated on the growth of M. ruber in the brine of stored table olives using a response surface methodology. A full 24 factorial design with three central points was first used in order to screen for the important factors (significant and marginally significant factors) and then a Face-Centered Central Composite Design was applied. Both preservatives prevented fungal spoilage, but potassium sorbate was the most efficient to control the fungi growth. The combined use of these preservatives did not show a synergistic effect. The results showed that the use of these salts may not be sufficient to prevent fungal spoilage and the greatest fungal growth was recorded at 30°C.

Effects of microwave-assisted hot water treatments designed against Mexican fruit fly (Anastrepha ludens) on grapefruit (Citrus paradisi) quality.

BACKGROUND: Hot water treatment (HWT) against Anastrepha ludens was developed achieving 48 °C in the core of grapefruits and holding it for 6 min. After heating, the grapefruits were hydro-cooled and stored at 23 °C and analyzed for 16 days. The effect of microwave-assisted HWT (MW-HWT) on grapefruit quality was analyzed and compared with the quality of fruits treated with HWT and control fruits (without treatment). The physicochemical properties and chemical composition of essential oil were analyzed. RESULTS: MW-HWT was equivalent to HWT according to accumulated heat calculations, with the advantage of being shorter. Treatments significantly affected the weight, color, maturity index, juice content, firmness, titratable acidity, pH, and ascorbic acid content of the grapefruits (P < 0.05), but had no effect on the total soluble solids (P > 0.05). The major components identified in the essential oil were d-limonene and ß-myrcene, compounds responsible of the scent of the grapefruits. CONCLUSION: MW-HWT was shorter (130 min) and had a lesser effect on the quality of the grapefruit when compared with fruits under HWT (188 min duration). Thus, this treatment could be considered as an alternative method against the Mexican fruit fly in grapefruit. © 2017 Society of Chemical Industry.

Antibacterial efficacy of nisin, bacteriophage P100 and sodium lactate against Listeria monocytogenes in ready-to-eat sliced pork ham

ABSTRACT The effectiveness of bacteriophage P100, nisin and sodium lactate, individually and in combination, in inhibiting Listeria monocytogenes in ready-to-eat pork ham slices was assessed. The antimicrobials were applied to the surfaces of ready-to-eat pork ham slices, which were inoculated with a mixture of L. monocytogenes. Among the individual antimicrobial treatments, bacteriophage P100 was the most effective, decreasing L. monocytogenes to undetectable levels at zero and 72 h post-infection. Sodium lactate was the least effective treatment. Treatment with nisin at zero h significantly reduced initial cell density (p < 0.05). However, this pattern was not observed at 72 h of storage. A significant difference (p < 0.05) existed between the results of separate bacteriophage and nisin treatments after refrigerated storage, but not immediately upon inoculation of the bacteria. The results showed that the use of bacteriophage P100 is the method of choice for the control of bacteria.

Antibacterial efficacy of nisin, bacteriophage P100 and sodium lactate against Listeria monocytogenes in ready-to-eat sliced pork ham.

The effectiveness of bacteriophage P100, nisin and sodium lactate, individually and in combination, in inhibiting Listeria monocytogenes in ready-to-eat pork ham slices was assessed. The antimicrobials were applied to the surfaces of ready-to-eat pork ham slices, which were inoculated with a mixture of L. monocytogenes. Among the individual antimicrobial treatments, bacteriophage P100 was the most effective, decreasing L. monocytogenes to undetectable levels at zero and 72h post-infection. Sodium lactate was the least effective treatment. Treatment with nisin at zeroh significantly reduced initial cell density (p<0.05). However, this pattern was not observed at 72h of storage. A significant difference (p<0.05) existed between the results of separate bacteriophage and nisin treatments after refrigerated storage, but not immediately upon inoculation of the bacteria. The results showed that the use of bacteriophage P100 is the method of choice for the control of bacteria.