Food and Bioprocess Technology

Experimental and Numerical Study of the Evolution of Carrot Texture during Cooking in a Pressure Cooker Abstract This study deals with changes to the food texture of carrot (Daucus carota) during steam cooking in a pressure cooker. A previously developed thermal pressure cooker model was used to predict the temperature evolution of the product from core to surface. This compartment model took into account heat and mass transfer laws and various phenomena to adequately describe pressure cookers’ mode of operation. In addition, a model predicting texture evolution as a function of the time-temperature history was proposed and its parameters were determined from experimental measurements in a standard Kramer cell after homogeneous cooking in a water bath. Combining the two models enabled an estimate of the degree of cooking from core to surface of the product as a function of cooking time. A volume averaged value for the degree of cooking was generated and permitted a good prediction of texture by comparison with the Kramer cell measurements. The combined model can be used to compare different cooking conditions reaching the same final texture.

Probing the Functionality of Bioactives from Eggplant Peel Extracts Through Extraction and Microencapsulation in Different Polymers and Whey Protein Hydrolysates Abstract Eggplant peels (Solanum melongena L.) constitute a promising source of phenolic compounds, flavonoids, and anthocyanins that are beneficial for human health. The objectives of this study were to extract the polyphenolics from eggplant peels and microencapsulation in selected polymers, such as pectin, carboxymethylcellulose and whey proteins hydrolysates by freeze-drying. A combination of ethanolic with ultrasound-assisted methods was used for the extraction, leading to an extract with antioxidant activity of 157.82 ± 9.46 mmol Trolox/g dry weight. The next experiment was to obtain bioactive peptide, both by experimental and predictive methods, which were further used as coating materials. The bioinformatics tools were used for checking the susceptibility of α-lactalbumin and β-lactoglobulin for digestion with thermolysin. The anthocyanins were encapsulated in different combinations of selected polymers, with encapsulation efficiency up to 77.60 ± 1.92%, highlighting a higher microencapsulation efficiency of carboxymethylcellulose to incorporate anthocyanins. Our results suggested whey peptides had a role in regulating the microencapsulation patterns, whereas carboxymethylcellulose and pectin favored filamentous structuring and double encapsulation, respectively. The in vitro tests showed high biocompatibility of powders cultivated in a cell culture of murine fibroblasts. A significant protective effect in simulated digestion was observed, with a controlled release in the intestinal juice. Accelerated storage stability test showed an increase in antioxidant activity.

Production of Antibacterial Coatings Through Atmospheric Pressure Plasma: a Promising Alternative for Combatting Biofilms in the Food Industry Abstract One of the main problems in the food industry is the formation of biofilms on food contact surfaces. These bacterial communities show high resistance against the commonly used disinfectants, which makes them difficult to eradicate causing economic losses and threatening the quality of the products and the health of consumers. Several studies have reported the use of atmospheric pressure plasma technologies to provide antibacterial properties to a wide range of materials through the deposition of coatings that either avoid the initial attachment of bacteria to the surface or kill the attached bacteria before the mature biofilm is formed. These technologies avoid the use of extreme pressures and temperatures during the deposition process, thus preserving the properties of the substrate, which makes them interesting for their potential application in the production of anti-biofilm food contact materials. This paper reviews different approaches that use atmospheric pressure plasma technologies to combat bacterial colonization and biofilm formation on materials of relevance for the food industry. Three types of approaches are identified and their suitability in the food industry is discussed.

Study of Static Steam Explosion of Citrus sinensis Juice Processing Waste for the Isolation of Sugars, Pectic Hydrocolloids, Flavonoids, and Peel Oil Abstract In this work, citrus juice processing waste (CPW) from a local Florida processor was subjected to steam explosion using a static bench scale reactor at 130, 150, and 170 °C for 1, 2, 4, and 8 min hold times with the aim of identifying conditions necessary for maximizing the recovery of sugars, pectic hydrocolloids, flavonoids, and peel oil. Sugars in steam-exploded CPW, from two harvests each of Hamlin and Valencia oranges, were extracted using water or enzymatic hydrolysis. Hydrolysis resulted in a 32–39% increase in total sugars. While hydrolysis increased the amount of glucose or fructose, it did not necessarily reduce the temperatures and or hold times at which the maximum amounts of sugar were recovered. Peel oil in raw CPW was reduced by as much as 94% using steam explosion and has the potential to be recovered by condensation. More galacturonic acid was recovered at 150 and 170 °C and 1 min treatment time for both Hamlin and Valencia CPW but led to increased molecular weight, suspected to be caused by aggregation, and decreased intrinsic viscosity. The higher temperatures and hold times also allowed vastly improved recoveries of the otherwise insoluble flavanone glycoside, hesperidin, with a maximum yield of 64,611 ppm dw CPW. Other potential value-added materials such as hydroxycinnamates and the health-benefiting polymethoxylated flavones are also recoverable in high percent yields in the water washes after steam explosion. Estimates are provided of the value of these recoverable products in the CPW of the 2016–17 Florida citrus season.

Phenolic Compound–Loaded Nanosystems: Artificial Neural Network Modeling to Predict Particle Size, Polydispersity Index, and Encapsulation Efficiency Abstract Artificial neural networks (ANNs) are a useful tool for the prediction of the particle size (PS), polydispersity index (PDI), and encapsulation efficiency (EE) of phenolic compounds (PC) in nanosystems because they consider the effects of all independent variables. This is very important for the prediction of the PS, PDI, and EE of nanosystems produced by ultrasound because the number of variables involved in the encapsulation process makes this prediction very complex. In this research work, three mathematical models for predicting the PS, PDI, and EE of PC in nanosystems produced by ultrasounds using ANN were developed. A database of scientific literature was used. These models allow the PS, PDI, and EE to be correlated mathematically with the PC mass; encapsulating copolymer concentration, ratio and mass; solvent volume; surfactant concentration; emulsion volume; and ultrasound time and power. The optimal configuration of the ANN consisted of a hidden layer with three, four, and two neurons in the hidden layer for PS, PDI, and EE, respectively. The models allowed us to predict PS, PDI, and EE for a wide range of factors. Mean square errors of 0.0538, 0.0337, and 0.0198 and correlation coefficients of 0.9139, 0.9064, and 0.8472 for PS, PDI, and EE, respectively, were obtained during training. Furthermore, mean square errors of 0.0408, 0.0224, and 0.0117 and correlation coefficients of 0.9138, 0.9115, and 0.8955 for PS, PDI, and EE, respectively, were achieved during verification.

A Novel Approach to Enhance Blueberry Quality During Storage Using Cold Plasma at Atmospheric Air Pressure Abstract Blueberry is an important health food, as it contains vitamins, anthocyanins, and antioxidative enzymes. However, post-harvest life of this fruit is very short, and its quality (in terms of microbial growth, antioxidant value, and decay rate) deteriorates rapidly during storage. In this work, air cold plasma at atmospheric pressure was evaluated as a pre-treatment approach for prolonging the shelf life and improving the quality of blueberries. After plasma treatment for 10 min, the number of bacteria and fungi decreased by 93.0% and 25.8%, respectively, which might be due to the increases in DNA damage and guanine oxidation. Accordingly, the blueberry decay rates reduced by 17.7%, 14.3%, and 5.2% in the plasma treatment groups of 6, 8, and 10 min, respectively, after 20 days of storage. Interestingly, the contents of sugar, vitamin C, and total anthocyanin as well as the superoxide dismutase activity level showed the maximum increases of 1.5-fold, 1.5-fold, 2.2-fold, and 79.3%, respectively, following different plasma discharge treatments and storage times compared with those in the control groups. Furthermore, in the treated samples, the degradation times for these four parameters to decrease to control levels were longer compared to the samples without treatment. These results indicated that air cold plasma at atmospheric pressure has excellent potential as a method for enhancing the quality and shelf life of fresh produce in the food industry.

Molecular Encapsulation of Eucalyptus staigeriana Essential Oil by Forming Inclusion Complexes with Hydroxypropyl-β-Cyclodextrin Abstract This study investigated the inclusion complex of Eucalyptus staigeriana essential oil (ESEO) formed with hydroxypropyl-β-cyclodextrin (HPCD) as a model system to determine which essential oil (EO) components were encapsulated in the complex. The ESEO/HPCD inclusion complex was prepared in aqueous solution and consequently analyzed by gas chromatography-mass spectrography (GC-MS), ultraviolet–visible spectroscopy (UV-VIS), thermogravimetric–differential thermal analysis (TG-DTA), 1H ROESY NMR, and molecular modeling. The results clearly showed that inclusion complexes had been successfully formed between ESEO and HPCD. It was demonstrated that the EO components did not form an inclusion complex with HPCD in equal proportions, but certain EO components were preferentially encapsulated. Components such as alcohols and aldehydes were preferentially encapsulated by HPCD, leading to higher concentrations of these compounds in the complex. This implies that encapsulation of EOs by forming inclusion complexes with HPCD may alter their composition in the complexes with potential changes in their properties such as antimicrobial activity.

Combined Use of Pectolytic Enzymes and Ultrasounds for Improving the Extraction of Phenolic Compounds During Vinification Abstract Phenolic compounds provide important quality attributes to red wines. These compounds are found inside the vacuoles of the plant cells of the skin and seeds of the grape. During maceration, they diffuse to the must/wine, although for this to happen, the vegetal cell walls need to rupture. Pectolytic enzymes and high-power ultrasound (US) may facilitate this objective. Therefore, this study analyzes the extraction efficiency of phenolic compounds using pectolytic enzymes and US (applied at 2 different times of the maceration period) alone and in combination. The chromatic characteristics of the wines were analyzed by spectrophotometry and chromatography at the end of the alcoholic fermentation and after 3 months in bottle. The treatment with enzymes alone increased the concentration of tannins by 13%, but US increased both the extraction of anthocyanins and tannins (7 and 16% respectively). The combination of enzymes and US, both applied at the beginning of the maceration time, did not improve the results of the treatments separately. However, when the enzyme was allowed to act alone during the first days of maceration before US was applied, a statistically significant synergistic effect was observed, increasing the color intensity by 18% and total phenol content by 21%, and especially marked was the effect on tannin extraction, whose concentration increased in the wines by 30% at the end of alcoholic fermentation.

Production of Functional Non-dairy Creamer using Nigella sativa oil Via Fluidized Bed Coating Technology Abstract Nigella sativa oil has a high potential to be developed into bioactive food ingredients. The aim of this study is to produce a low-fat, non-dairy creamer (NDC) from Nigella sativa oil (NSO) that is extracted by a supercritical fluid technique. The emulsion was processed with total solids of 40% and the drying process was performed using a spray dry technique at 160 °C inlet air temperature to obtain the microencapsulated oil. The agglomeration conditions (fluidizing time, fluid air temperature, and feed flow rate), were optimized using a response surface methodology (RSM) with a central composite design. The microencapsulated oil demonstrated low moisture content, high water solubility, strong antioxidant activity and high thymoquinone content in the developed creamer. The optimum conditions of the fluidized bed drying process were inlet air temperature (50 °C), drying time (25 min), and feed flow rate (1 mL/min). The sensory evaluation revealed that consumers’ acceptability is high for the developed coffee creamer. The findings indicated the high potential of the microencapsulated oil for applications to mass produce and commercialize functional non-dairy creamer.

Preparation of Hydrogels Composed of Bioactive Compounds from Aqueous Phase of Artichoke Obtained by MHG Technique Abstract This work deals with the valorisation of artichoke industrial wastes from natural and blanched processed samples to prepare innovative functional gelling matrices. For this purpose, the recovery of bioactive liquid phases using microwave hydrodiffusion and gravity (MHG) in a broad range of irradiation powers and the corresponding phytochemical and colour characterisations were conducted. Liquid phases with the highest bioactive compounds were used to formulate functional hydrogels. These gelled systems were mechanically characterised. Phytochemical analyses indicated that the highest bioactive features were identified for liquors collected from both natural and blanched samples MHG-treated at 500 W. The blanching pre-treatment favoured the bioactive compound recovery, without notable differences in terms of colour properties. In general, no significant differences (p > 0.05) were observed in energy consumption when MHG treatments for natural and blanched artichoke extractions were compared. In all selected cases, typical gel spectra were observed for bioactive liquid phases gelled using both alginate and gelatine. Softening of the gelled matrices was identified in the presence of bioactive extracts. Texture profile analyses for natural and blanched artichoke samples were consistent with the results obtained by rheology. Phytochemical and colour analyses indicated that frozen storage was an adequate method to preserve the bioactive properties of the samples for at least 3 years.