Comparison of physical, microstructural and antioxidative properties of pumpkin cubes cooked by conventional, vacuum cooking and sous vide methods.

BACKGROUND: Current dietary guidelines recommend five or more fruit, vegetable, and legume servings per day. Often, these products are eaten cooked, resulting in organoleptic and nutritional changes. Vacuum cooking is gaining attention as an alternative cooking technique, due to its ability to preserve or even enhance sensory and healthy properties of food. Its household application is, however, poorly explored. In this work, the effect of vacuum cooking, performed with a new patented system, was studied for the first time on pumpkin cubes and compared to sous vide and traditional steam cooking, through a multidisciplinary approach. RESULTS: All the cooking treatments damaged pumpkin microstructure, leading to cell separation and plasmolysis; vacuum cooking was the most aggressive method, as confirmed by texture softening. Vacuum cooking was also the method with less impact on pumpkin color, in relation to the largest extraction of some classes of carotenoids from the broken cells. Significant polyphenol extraction, especially of gallic acid and naringenin, was instead observed for sous vide and steamed pumpkins. The total antioxidant activity, ascribable to the effect of both carotenoids and polyphenols, resulted enhanced after cooking compared to raw one mainly for cook vide samples, followed by steamed and sous vide ones. CONCLUSIONS: Vacuum cooking, followed by sous vide, has often shown better performance than traditional steam cooking for pumpkin cubes. The implementation of sous vide and vacuum cooking at domestic level or in professional kitchens, and in the food industry, would allow the consumption of vegetables with improved nutritional and sensorial characteristics. © 2020 Society of Chemical Industry.

Application and optimisation of air-steam cooking on selected vegetables: impact on physical and antioxidant properties.

BACKGROUND: Several studies investigated the impact of different cooking techniques on the quality of vegetables. However, the use of the combined air-steam cooking is still scarcely debated, despite the advantages informally referred by professional catering workers. In this study, its optimisation was studied on Brussels sprouts and pumpkin cubes to obtain the best physical (texture, colour) and antioxidant (FRAP, total phenols) response, in comparison to a conventional steaming treatment. RESULTS: Increasing the strength of the air-steam treatment, Brussels sprouts resulted to be softer, less green (higher a* value), richer in phenols and exhibited lower FRAP values than the steamed ones. The air-steamed pumpkin cubes exhibited an equivalent softening degree to that of steamed ones and, under the strongest cooking conditions, a higher antioxidant quality and a yellow darkening (lower b* value). Varying the cooking time and/or temperature, a linear change of force/compression hardness and a* (negative a*: greenness) for Brussels sprouts, b* (yellowness) and total phenol content for pumpkin cubes was observed. A predictive model for these variables was obtained by response surface methodology. The best process conditions to achieve the optimal desirability were also identified. CONCLUSION: The application of air-steam cooking under suitable time/temperature conditions could be proposed as an alternative method to a traditional steam cooking on Brussels sprouts and pumpkin cubes, being able to preserve or improve their quality. The best air-steam cooking conditions were 25 min at 90 °C for Brussels sprouts and 10 min at 110 °C for pumpkin. © 2017 Society of Chemical Industry.

Investigation on temperature fields in industrial chilling of pork legs for PDO Parma ham production and coupled temperature/microbial growth simulation.

In the present work, temperature distribution within an industrial blast chiller with pork leg for Protected Designation of Origin Parma ham production was studied and the slowest cooling zone and the fastest cooling zone were recognized. Moreover, apparent heat transfer coefficients in both positions were calculated and resulted equal to 27.1 and 15.6 W m-2 °C-1, respectively. A finite element method model by distinguishing the three main components (skin, lean meat and bone) of the leg for the unsteady heat transfer during cooling was developed and validated against industrial chiller data. Good agreement between experimental and simulated data was obtained with RMSE value for thermal centre equal to 0.81 °C. Furthermore, in order to introduce CCP limit in the HACCP plan, a microbial growth model of the most important pathogens in meat was developed starting from the heat transfer model results. Temperature as well as pathogen growth were estimated in the case of different plant breakdowns. Defined CCP limit was represented by reaching 11 °C at 5 mm of depth within 2 h from the beginning of the cooling process, moreover a different cooling program was simulated and established as the alternative one.

Correlation between different markers for the assessment of red chilli pepper powders stability during shelf-life.

Pungency and red colour of Capsicum powders deteriorate during processing and storage, resulting in a decrease in market value. Two varieties of pepper with different pungencies were monitored for capsaicinoids, colour and furosine. Aliquots were stored at room and at low temperature during one year. At low temperature all indicators were stable in both varieties, while at room temperature, redness and capsacinoids decreased significantly, while furosine increased. High correlation was found between those markers. The more pungent variety exhibited higher stability in terms of all parameters. Differences observed suggest a potential protective effect exerted by capsaicinoids on powder stability. The decrease in capsaicinoids and redness accompanied by furosine increase showed a linkage between those markers never reported before. Considering that capsaicinoids and furosine occurrence have strong impact on the nutritional profile, the findings of this work show relevant changes in the nutritional value of chilli pepper powder after storage.

Short-term storage evaluation of quality and antioxidant capacity in chestnut-wheat bread.

BACKGROUND: Bread traditionally made from wheat is now often supplemented with alternative functional ingredients as chestnut flours; no data have been previously published about the staling of chestnut-containing bread. Thus short-term storage (3 days) for chestnut flour-supplemented soft wheat bread is evaluated by means of selected physicochemical properties (i.e. water dynamics, texture, colour, crumb grain characteristic, total antioxidant capacity). RESULTS: Bread prepared with a 20:80 ratio of chestnut:soft wheat flours maintained its moisture content in both crust and crumb. Crumb hardness, after baking, was found to be significantly higher than that of the soft wheat bread; it did not change during storage, whereas it significantly increased in the control bread until the end of the shelf life. The supplemented bread presented a heterogeneous crumb structure, with a significant decrease in the largest pores during shelf life, relative to the shrinkage of crumb grain. The control exhibited a significant redistribution of crumb holes, with a decrease in the smallest grain classes and an increase in the intermediate ones, most likely caused by cell wall thickening. The colour of the crumb remained unaltered in both breads. The crust of the control presented a significant decrease of a* (redness) and that of the supplemented bread exhibited a decrease of b* (yellowness). The antioxidant capacity was detected after day 1 of storage in the chestnut flour bread only. CONCLUSION: Chestnut flour supplementation could represent a feasible way of producing bread with improved characteristics, not only just after baking but also during shelf life.

Effects of alternative steeping methods on composition, antioxidant property and colour of green, black and oolong tea infusions.

Cold water steeping is reported to maximise tea health benefits, but requires long infusion time. In this work, the employment of a brief hot infusion step followed by ice addition was evaluated. The comparison of this innovative method with hot and cold steeping was investigated on green, black and oolong teas. Catechins, xanthines and gallic acid content, antioxidant power, total phenolics and colour analysis were evaluated. Hot infusion shown rapid extractive power, but relevant compound degradation. On the contrary, cold infusion extracted higher level of healthy molecules with slow kinetic. The innovative method achieved in short time similar properties of cold infusion in terms of antioxidant power. As for bioactive compounds, such as gallic acid and epigallocatechin gallate, highest values, about double than in hot infusion, were recorded for green and black teas. This steeping method may represent an alternative approach for industrial beverage preparation.

Durum and soft wheat flours in sourdough and straight-dough bread-making.

In the present work, the bread-making performance of durum wheat flour under straight-dough and sourdough procedures were compared to those offered by soft wheat flour by means of selected physical properties (colour, texture, water dynamics, crumb grain characteristic, bulk volume) immediately after baking and during a 5-day shelf-life. The use of sourdough process better preserved both crumb grain characteristic and moisture content of the breads during shelf-life, independently of the wheat flour used. The flour seemed to significantly affect the water dynamics in sourdough breads, being the dehydration process of crust and under-crust faster in durum wheat breads. On the other hand, increasing trend of crumb firmness during the shelf-life was slower in durum wheat breads than in those obtained with soft wheat flour. Initial colour parameters of crust and crumb appeared to less change during shelf-life if durum wheat flour was used. Thus, the final quality of breads after baking and along the shelf-life was significantly affected by both the type of flours and the bread-making process. The results reported herein showed that technological performances of durum wheat flour, especially when combined with sourdough processes, could be successfully exploited for the production of innovative products in the bread-making industry.

Particlelike distributions of the Higgs field nonminimally coupled to gravity.

When the Higgs field is nonminimally coupled to gravity, there exists a family of spherically symmetric particlelike solutions to the field equations. These monopoles are the only globally regular and asymptotically flat distributions with finite energy of the Higgs field around compact objects. Moreover, spontaneous scalarization is strongly amplified for specific values of their mass and compactness.

Cosmology and Fundamental Physics with the Euclid Satellite.

Euclid is a European Space Agency medium-class mission selected for launch in 2019 within the Cosmic Vision 2015-2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and red-shifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid's Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.

Stability of iodine during cooking: investigation on biofortified and not fortified vegetables.

Biofortification of food crops through fertilization and salt iodization are key strategies for the prevention and control of iodine deficiency disorder. However, considerable losses of iodine can occur during processing. In this study, the stability of iodine in biofortified potatoes, carrots and tomatoes was evaluated during different domestic cooking procedures, as this matter was poorly discussed in literature. The stability of iodized salt during baking and boiling of carrots and potatoes not fortified was also investigated. All the adopted cooking procedures have proven to be suitable to preserve the iodine content in biofortified vegetables. During boiling test with iodized salt, neither potatoes nor carrots were able to absorb iodine added with salt, probably owing to the losses occurred during cooking. On the contrary, baking test on potatoes has not caused a significant degradation of iodized salt, and no significant differences in iodine concentration were detected before and after cooking.

Impact of Combined Thermal Pressure Treatments on Physical Properties and Stability of Whey Protein Gel Emulsions.

Emulsion gels are gaining interest as fat replacers due to their benefits associated with calorie reduction and their versatility in a wide range of products. Their production process needs to be tailored to obtain the desired stability and physicochemical properties. This study investigated the effect of heat (70, 80, and 90 °C) and pressure (5, 10, and 15 MPa) to produce whey protein emulsion gels using a pilot-scale tubular heat exchanger equipped with a homogenization valve. Both temperature and pressure determined a significant effect (p < 0.05) on the rheological moduli, with the treated samples displaying a predominant elastic behavior. The treatments also showed an improved pseudoplasticity due to the significant reduction in the flow behavior index (p < 0.05). All the samples showed a bimodal particle size distribution; by increasing the temperature up to 80 °C, a reduction in Dv50 (50th percentile) values compared to the control samples was observed. At 90 °C, the Dv50 value increased because of coalescence and flocculation phenomena occurring during or immediately after processing. The greater aggregation and structural development obtained with stronger process conditions improved the stability of the emulsions. The results show the capability to produce gel emulsions with good physical properties that could be proposed as food ingredients to substitute fats in food products.

Understanding the Impact of High-Pressure Treatment on Physico-Chemical, Microstructural, and Microbiological Aspects of Pumpkin Cubes.

In this study color, texture, starch-pectin, total antioxidant capacity, microbial count, and microstructure of HPP-treated Violina pumpkin cubes were evaluated. Samples were treated at six different pressures (100 to 600 MPa-HPP100 to HPP600) for 3 min. Moisture, total soluble solids, and pH showed no significant differences between untreated (UNTR) and treated samples. Pumpkin tissue showed great structural modifications as changes in cell size and shape, cell wall damage, increased cell wall thickness, cell detachment and dehydration, and calcium ions deposition mainly from HPP300 to 600. UNTR samples showed the highest value of maximum and minimum cell elongation, perimeter segment, and a more regular cell wall thickness whereas HPP600 showed the lowest values for all these parameters. A noticeable difference was observed in HPP600 samples, with a difference in terms of color (ΔE 11.3 ± 1.9) and hardness (87.4 ± 27.8 N) compared to the UNTR ones (194.9 ± 37.9 N) whereas treatments at other pressures changed less markedly the color and texture. HPP200 could ensure a higher amount of starch and pectin availability while HPP200 and HPP400 showed the highest total antioxidants capacity. High-pressure treatment from HPP400 to 600 gave the highest destruction of microorganisms but negatively influenced the structural quality as well as texture and microstructure.

Effect of different atmospheric and subatmospheric cooking techniques on physical and chemical qualitative properties of pork loin.

In this paper, the effects of four cooking procedures were evaluated, two occurring in atmospheric (in ventilated and steam oven) and two in subatmospheric (vacuum and sous vide cooking) conditions on pork Longissimus lumborum. The main objective of the study was to compare and evaluate the physical and chemical characteristics. Samples were cooked in four independent trials namely Oven (O), Steaming (ST), Vacuum Cooking (VC) and Sous Vide (SV). The analyses included temperature, cooking effect, percentage weight loss, texture (cutting and double compression tests), colour (superficially and inside the sample), microstructure (optical microscopy) and fibres shortening analysis. To assess cooking effects on significant nutritional constituents, the fatty acid composition and the content of B vitamins were analysed. Volatile profiles of samples were also compared using solid-phase microextraction. SV cooking resulted in the less favourable meat texture, presenting the highest hardness and chewiness. Moreover, high hardness values measured on SV samples is also related to the high weight loss. The technique of oven cooking (O) demonstrated superior results in terms of mechanical properties, which are closely associated with the cooking values. Specifically, the cook value C0 was significantly higher in the case of oven cooking compared to SV, VC, and ST. Mild temperature conditions and cooking times of the four considered cooking techniques did not induce significant variations in the fatty acid composition and volatile profile. Conversely, SV and VC allowed the highest amount of vitamin B retention in cooked meat. This work suggests that some differences emerged on the effects due to sub-atmospheric and atmospheric cooking compared to traditional ones.

Fresh-Cut Eruca Sativa Treated with Plasma Activated Water (PAW): Evaluation of Antioxidant Capacity, Polyphenolic Profile and Redox Status in Caco2 Cells.

Plasma Activated Water (PAW) has recently emerged as a promising non-chemical and non-thermal technology for the microbial decontamination of food. However, its use as a replacement for conventional disinfection solutions needs further investigation, as the impact of reactive species generated by PAW on nutritional food quality, toxicology, and safety is still unclear. The purpose of this study is to investigate how treatment with PAW affects the health-promoting properties of fresh-cut rocket salad (Eruca sativa). Therefore, the polyphenolic profile and antioxidant activity were evaluated by a combination of UHPLC-MS/MS and in vitro assays. Moreover, the effects of polyphenolic extracts on cell viability and oxidative status in Caco2 cells were assessed. PAW caused a slight reduction in the radical scavenging activity of the amphiphilic fraction over time but produced a positive effect on the total phenolic content, of about 70% in PAW-20, and an increase in the relative percentage (about 44-50%) of glucosinolate. Interestingly, the PAW polyphenol extract did not cause any cytotoxic effect and caused a lower imbalance in the redox status compared to an untreated sample. The obtained results support the use of PAW technology for fresh-cut vegetables to preserve their nutritional properties.

Semi-Empirical Mathematical Modeling, Energy and Exergy Analysis, and Textural Characteristics of Convectively Dried Plantain Banana Slices.

Thin-layer convective drying of plantain banana was performed at four different temperatures from 50 to 80 °C, with slice thicknesses from 2 to 8 mm. The drying curves, fitted to seven different semi-empirical mathematical models, were successfully used to fit experimental data (R2 0.72−0.99). The diffusion approach had better applicability in envisaging the moisture ratio at any time during the drying process, with the maximum correlation value (R2 0.99) and minimum value of x2 (2.5×10−5 to 1.5×10−4) and RMSE (5.0 ×10−3 to 1.2×10−2). The Deff, hm, and Ea values were calculated on the basis of the experimental data, and overall ranged from 1.11×10−10 to 1.79×10−9 m2 s−1, 3.17×10−8 to 2.20 ×10−7 m s−1 and 13.70 to 18.23 kJ mol−1, respectively. The process energy consumption varied from 23.3 to 121.4 kWh kg−1. The correlation study showed that the drying temperature had a close correlation with hm value and sample hardness. A significant (p < 0.05) increase in hardness of dried plantain banana was observed at 80 °C compared to the other temperatures. Additionally, the sample hardness and process energy consumption were more positively correlated with the thickness of the samples.

Differential scanning calorimetry thermal properties and oxidative stability indices of microwave heated extra virgin olive oils.

BACKGROUND: The use of differential scanning calorimetry (DSC) for assessing the deterioration effect of microwave heating on vegetable oils, and on olive oils in particular, has been partially explored in literature. The aim of this work was to evaluate the potential of DSC to discriminate among microwaved extra virgin olive oils (EvOo from different olive cultivar and origin), according to changes on thermal properties (upon cooling and heating) and traditional oxidative stability indices (peroxide, p-anisidine and TOTOX values). RESULTS: An elevated value of lipid oxidation was reached by the most unsaturated EvOo sample (9.5% of linoleic acid) at 6 min of microwave treatment. Free acidity significantly increased (0.42%) only for the oil sample with the highest water content (874 mg kg(-1) oil) at the longest time of treatment. Crystallisation enthalpies significantly decreased and the major exothermic peak shifted towards lower temperature, leading to enlargement of the transition range in all samples due to the formation of weak and mixed crystals among triacylglycerols and lipid degradation products. On the contrary, thermal properties upon heating appeared to similarly vary among samples. CONCLUSIONS: The analysis of DSC thermal properties upon cooling seemed to clearly discriminate among different EvOo samples after microwaving. The relation between changes of thermal properties and oxidation parameters should be further studied using additional oxidative stability indices on a larger set of oil samples, due to the complexity of EvOo composition.

Effects of Thermal and High-Pressure Processing on Quality Features and the Volatile Profiles of Cloudy Juices Obtained from Golden Delicious, Pinova, and Red Delicious Apple Cultivars.

In this study, juices extracted from three apple cultivars (Golden Delicious, Pinova, and Red Delicious) were stabilized by means of thermal treatment (TT) and high-pressure processing (HPP, 600 MPa 3 min); pH, total titratable acidity, total soluble solids content, color, and viscosity, as well as volatile profile, were investigated. Qualitative characteristics (pH, titratable acidity, colorimetric parameters, viscosity, and volatile profile) results were significantly influenced by both cultivars and treatments; for example, juice viscosity greatly increased after HPP treatment for Golden Delicious, and after both TT and HPP for Pinova, while no influence of stabilization treatment was registered for Red Delicious juices. Regarding the volatile profile, for Golden Delicious cultivar, HPP treatment determined an increase in volatile compounds for most of the classes considered, leading to a supposed quality implementation. For the other two cultivars, the stabilization treatment that better preserved the volatile profile was the HPP one, even if the results were quite similar to the thermal treatment. Further studies are needed to evaluate different time/pressure combinations that could give better results, depending on the specific apple cultivar.

Effects of different maturity stages on antioxidant content of Ivorian Gnagnan (Solanum indicum L.) berries.

Gnagnan (Solanum indicum L.) is a spontaneous plant widely distributed in Ivory Coast. During ripening stages, Solanum indicum L. presents different colours (green, yellow and red) and is reported to contain several albeit poorly characterized antioxidant compounds. This paper describes in detail the antioxidant profile (ascorbic acid, carotenoids and polyphenols), antioxidant capacity (FRAP test and Folin-Ciocalteau assay) and the colour changes of Gnagnan berries at different ripening levels. Ascorbic acid content was similar in green and yellow berries, but significantly lower in red ones. Red berries showed a higher content of carotenoids compared to green and yellow ones. Regarding polyphenols, several phenolic acids and flavonoids were found in all berries. The content of caffeoylquinic acids, caffeic acid, flavonol glycosides and naringenin was higher in red berries, while the content of p-coumaric acid and feruloylquinic acids was similar among the three colours. The FRAP assay increased with the ripening process, whereas total polyphenols were similar among berries. Significant differences were found for the colorimetric indexes among products of different degrees of ripening. The present results show the important role of the ripening stage in increasing the antioxidant content of Gnagnan berries.

Effect of Addition of Green Coffee Parchment on Structural, Qualitative and Chemical Properties of Gluten-Free Bread.

Green coffee parchment (GCP) is becoming interesting, due to the diffusion of wet processing in which coffee parchment is collected separately; it is one of the less studied coffee by-products, but it is reported to be rich in phenolic compounds and dietary fiber. The addition of GCP (355-500 µm) at 2 % to gluten-free breads was investigated in terms of physical properties (volume, moisture content, water activity, crumb grain, texture, and color), total antioxidant capacity (TAC) and total phenol content during three days of storage. Moreover, the effects of GCP on sensorial characteristics, 5-hydroxymethylfurfural (HMF), and oxidative stability was evaluated. From the sensorial analysis, bread with 2% addition resulted in being acceptable for consumers with no significant differences from the control, while 4% of GCP was discarded by consumers, as it resulted in being too bitter. Moreover, GCP at 2% addition did not modify volume, moisture content, and water activity. On the contrary, GCP deeply affected the color with a darker aspect that was appreciated by consumers. Regarding texture, 2% of GCP did not affect hardness, cohesiveness, and staling process during storage. Interestingly, 2% of GCP significantly improved the TAC and oxidative stability of the bread; in accordance with these results, 2% of GCP reduced the HMF content, thanks to its antioxidant compounds.

Volatile fingerprint of unroasted and roasted cocoa beans (Theobroma cacao L.) from different geographical origins.

The aroma characterization of 58 unroasted cocoa beans from 22 different geographical origins was performed by head space solid phase micro-extraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). Sampling is representative of the average world production (America, Africa, and Southeast Asia). Analysis of cocoa beans before and after roasting were performed to follow the aroma modification with the aim to achieve a cocoa volatile fingerprint and a discrimination model based on beans origin. A total of 57 volatiles was identified in unroasted cocoa beans, while 71 volatiles were identified in roasted cocoa beans. The compounds belong to several chemical groups including esters, alcohols, organic acids, aldehydes, ketones and pyrazines. Datasets were submitted to multivariate statistical analysis (Principal Component Analysis, PCA). Results allowed to discriminate unroasted cocoa beans based on their geographical origin: samples coming from African countries were separated from samples of American regions, whereas samples from Southeast Asia lie between the other two continents suggesting that Asian samples have intermediate characteristics between African and South American cocoa beans. PCA, applied on the corresponding roasted samples, showed that although the same roasting treatment has been applied to all the samples, the differences among the unroasted samples were also maintained in the aromatic profile after roasting. The discrimination model based on volatile fingerprint combined with chemometric tools, showed interesting potential for origin authentication of both unroasted and roasted cocoa beans.