Multilayer microparticles for programmed sequential release of phenolic compounds from Eugenia stipitata: Stability and bioavailability.

A co-delivery system based on multilayer microparticles was developed and characterized for the sequential release of phenolic compounds (PCs) using different encapsulation processes (spray drying: SD and drying-chilling spray: SDC) and wall materials to improve the stability and bioavailability of PCs. Samples were characterized in terms of process yield (PY%), phenolic retention efficiency (PRE%), chemical structure and crystallinity (NMR, FTIR, DXR), thermal stability (DSC and FT-IR), anti-radical capacity (ORAC and ABTS) and in vitro digestion. PRE% of samples by SD were higher (p < 0.05) than SDC due to the formation of PCs from CRF (cará-roxo flour). NMR, FTIR, DXR confirmed the presence of key components and interactions for the formation of the advanced co-delivery system. The SDC particles showed crystalline regions by XRD and were stable at ∼47 °C. All samples showed good release of PC in the intestinal phase, and antiradical capacity that reached 23.66 µmol TE g-1.

Freeze-Dried Banana Slices Carrying Probiotic Bacteria.

Findings on diet-health relationships have induced many people to adopt healthier diets, including the substitution of energy-dense snacks with healthier items, e.g., those containing probiotic microorganisms. The aim of this research was to compare two methods to produce probiotic freeze-dried banana slices-one of them consisting of impregnating slices with a suspension of probiotic Bacillus coagulans, the other based on coating the slices with a starch dispersion containing the bacteria. Both processes resulted in viable cell counts above 7 log ufc.g-1, although the presence of the starch coating prevented a significant loss in viability during freeze-drying. The coated slices were less crispy than the impregnated ones, according to the shear force test results. However, the sensory panel (with more than 100 panelists) did not perceive significant texture differences. Both methods presented good results in terms of probiotic cell viability and sensory acceptability (the coated slices being significantly more accepted than the non-probiotic control slices).

Correction: Freitas et al. Bacterial Cellulose/Tomato Puree Edible Films as Moisture Barrier Structures in Multicomponent Foods. Foods 2022, 11, 2336.

In the original publication [...].

Edible films and coatings - Not just packaging materials.

Edible films and coatings (EFC) are macromolecular-based structures forming thin layers that are usually studied as tools to improve food stability, sometimes being considered as parts of both the packaging system and the food itself. However, EFC are not mere packaging materials, and sometimes they do not even play roles related to those of packaging. This graphical review summarizes possible roles of EFC, including primary packaging, keeping water activity gradients between food components, controlling mass transfer on food processing, carrying active components, or serving as sources of sensory appeal. EFC may even be designed in a way that two or more of those roles may be played simultaneously.

Bacterial Cellulose/Tomato Puree Edible Films as Moisture Barrier Structures in Multicomponent Foods.

Edible films have been studied mainly as primary packaging materials, but they may be used as barrier layers between food components, e.g., by reducing the moisture migration between components with contrasting water activities. Since edible films are part of the food itself, components adding sensory appeal (e.g., fruit purees) are usually desirable. The objective of this study was to develop a film to be applied as a moisture barrier between nachos and guacamole. Ten film formulations were prepared according to a simplex centroid design with three components-a polysaccharide matrix (consisting of a 5:1 mixture of bacterial cellulose-BC-and carboxymethyl cellulose), tomato puree (for sensory appeal), and palm olein (to reduce hydrophilicity)-and produced by bench casting. The film with the highest palm olein content (20%) presented the lowest water vapor permeability, and its formulation was used to produce a film by continuous casting. The film was applied as a layer between nachos and guacamole, and presented to 80 panelists. The film-containing snack was preferred and considered as crispier when compared to the snack without the film, suggesting that the film was effective in reducing the moisture migration from the moist guacamole to the crispy nachos.

Smart choices: Mechanisms of intelligent food packaging.

Intelligent food packaging is usually designed to monitor the state of the food itself and/or the environment around it, as well as the interactions between them, providing customers with information on food quality and/or safety through a variety of signals. They involve indicators (which inform by direct visual changes about specific properties related to food quality) and sensors (which detect specific analytes by using receptors, transducers, and signal processing electronics). A third type of intelligent packaging is known as data carriers, which are not typically used for information on food quality, but rather to track the movement of food along the food supply chain. In this graphical review, the basic mechanisms of intelligent food packaging systems are presented, as well as their main applications, with particular emphasis on those focused on food quality monitoring.

The Food-Materials Nexus: Next Generation Bioplastics and Advanced Materials from Agri-Food Residues.

The most recent strategies available for upcycling agri-food losses and waste (FLW) into functional bioplastics and advanced materials are reviewed and the valorization of food residuals are put in perspective, adding to the water-food-energy nexus. Low value or underutilized biomass, biocolloids, water-soluble biopolymers, polymerizable monomers, and nutrients are introduced as feasible building blocks for biotechnological conversion into bioplastics. The latter are demonstrated for their incorporation in multifunctional packaging, biomedical devices, sensors, actuators, and energy conversion and storage devices, contributing to the valorization efforts within the future circular bioeconomy. Strategies are introduced to effectively synthesize, deconstruct and reassemble or engineer FLW-derived monomeric, polymeric, and colloidal building blocks. Multifunctional bioplastics are introduced considering the structural, chemical, physical as well as the accessibility of FLW precursors. Processing techniques are analyzed within the fields of polymer chemistry and physics. The prospects of FLW streams and biomass surplus, considering their availability, interactions with water and thermal stability, are critically discussed in a near-future scenario that is expected to lead to next-generation bioplastics and advanced materials.

From cashew byproducts to biodegradable active materials: Bacterial cellulose-lignin-cellulose nanocrystal nanocomposite films.

While the cashew culture is focused on processing and commercialization of cashew nuts, the pseudofruit (cashew apples) - highly perishable and of limited acceptance - are mostly wasted. The cashew tree pruning fiber (CTPF) is another interesting cashew byproduct. In this study, films have been made from bacterial cellulose produced from cashew apple juice, and added with lignin (0-15 wt%) and cellulose nanocrystals (0-8 wt%), both from CTPF, which enhanced tensile properties and decreased water vapor permeability of the films. Moreover, lignin, although imparting brown color and opacity to the films, was effective to provide the films with UV-absorbing and antioxidant properties, making the films interesting for packaging of food products susceptible to lipid oxidation. The films did not exhibit antimicrobial activity against bacteria or yeasts.

Nanostructured Antimicrobials in Food Packaging-Recent Advances.

Active food packaging systems promote better food quality and/or stability, such as by releasing antimicrobial agents into food. Advantages of adding antimicrobials to the packaging material instead of into the bulk food include controlled diffusion, reduced antimicrobial contents, and improved cost effectiveness. Nanostructured antimicrobials are especially effective due to their high specific surface area. The present review is focused on recent advances and findings on the main nanostructured antimicrobial packaging systems for food packaging purposes. Several kinds of nanostructures, including both inorganic particles and organic structures, have been proven effective antimicrobials by different mechanisms of action and with different application scopes. Moreover, there are systems containing nanocarriers to protect antimicrobials and deliver them in a controlled fashion. On the other hand, scientific data about migration of nanostructures onto food and their toxicity are still limited, requiring special attention from researchers and regulation sectors.

Mango kernel starch films as affected by starch nanocrystals and cellulose nanocrystals.

Mango seeds have been used to obtain components for nanocomposite films, namely, starch and starch nanocrystals (SNC) from seed kernels, and cellulose nanocrystals (CNC) from seed shells. Lignin was also recovered from shells. Starch-based films were prepared with different contents and combinations of SNC and CNC. SNC exhibited round-like rather than platelet-like morphology, and their effect on water vapor barrier was not as high as that of the needle-like CNC. Also, CNC were more effective than SNC to increase elastic modulus. On the other hand, CNC impaired more the elongation. The optimized conditions (1.5 wt% CNC and 8.5 wt% SNC on a starch basis) resulted in a film with enhanced strength, modulus, and barrier to water vapor when compared to the unfilled film, although the elongation has been impaired.

Nanofibrillated bacterial cellulose and pectin edible films added with fruit purees.

Bacterial cellulose (BC) is a water resistant and strong material for edible films. Previous studies have been conducted on edible films containing fruit purees, but not using BC. In this study, films with or without fruit (mango or guava) purees were prepared using different ratios of nanofibrillated BC (NFBC) to pectin. The addition of fruit purees increased water vapor permeability (in about 13-18 times), reduced tensile strength (in more than 90%) and modulus (in about 99%), and increased elongation (in about 13 times), due to plasticizing effects of fruit sugars and matrix dilution by the purees. The partial or total replacement of pectin with NFBC resulted in improved physical properties, making the films stronger, stiffer, more resistant to water, and with enhanced barrier to water vapor. Fruit containing films based on pectin are suggested for sachets, whereas applications for food wrapping or coating may benefit from the use of NFBC.

Enhancing storage stability of guava with tannic acid-crosslinked zein coatings.

The quality of zein (Z)- and zein-tannic acid (ZTA)-coated guavas was monitored throughout 12 days of storage. Coated fruit showed lower changes in terms of visual appearance, chlorophyll contents and color. Weight loss, softening, and changes in soluble solids were also decreased by the coatings. The respiration peak as well as H2O2 and superoxide dismutase activity peaks were delayed by the coatings, and the ethylene production was reduced. So, the results were consistent with a slowed down ripening of guavas by the coatings, which was probably related to lowered oxygen permeability of guava skin. ZTA coating was more effective than Z to reduce weight loss, softening, color changes, ethylene production, and oxidative stress. The higher efficiency of ZTA coating was ascribed to zein crosslinking, which probably resulted in decreased gas permeability, promoting lower respiration rates and lower ROS production, slowing down the ripening process, and extending guava stability.

Stabilizing effect of montmorillonite on acerola juice anthocyanins.

This study was conducted to evaluate color and anthocyanin stability of clarified acerola juice (CAJ) as affected by montmorillonite (Mnt) at different concentrations (0-6 wt%, dry basis). While non-complexed CAJ suffered noticeable color degradation with time and pH variations, the presence of Mnt (especially at 4-6 wt%) not only changed the initial color of CAJ but also made it more stable with time and pH changes. CAJ/Mnt mixtures were ultracentrifuged in order to separate them into supernatants and anthocyanin-complexed Mnt precipitates. The supernatants presented decreasing anthocyanin contents with increasing Mnt concentrations, indicating pigment retention by the precipitates. X-ray diffraction of precipitates showed that Mnt interlayer spacing was increased by increasing anthocyanin/Mnt ratios, corroborating anthocyanin intercalation. FTIR revealed a band at 1530 cm-1 ascribed to formation of anthocyanin-Mnt complexes. Moreover, chromatograms indicated the selective adsorption of two compounds by Mnt, which were identified by LC-MS as cyanidin-3-O-rhamnoside and pelargonidin-3-O-rhamnoside.

Bionanocomposite films based on polysaccharides from banana peels.

Pectin and cellulose nanocrystals (CNCs) isolated from banana peels were used to prepare films. The effects of a reinforcing phase (CNCs) and a crosslinker (citric acid, CA) on properties of pectin films were studied. Glycerol-plasticized films were prepared by casting, with different CNC contents (0-10wt%), with or without CA. Overall tensile properties were improved by intermediate CNC contents (around 5wt%). The water resistance and water vapor barrier properties were also enhanced by CNC. Evidences were found from Fourier Transform Infrared (FTIR) spectra supporting the occurrence of crosslinking by CA. Additionally, the tensile strength, water resistance and barrier to water vapor were improved by the presence of CA. The 13C ssNMR spectra indicated that both CA and CNC promoted stiffening of the polymer chains.

Wheat straw hemicelluloses added with cellulose nanocrystals and citric acid. Effect on film physical properties.

Wheat straw has been used as a source of hemicelluloses (WSH) and cellulose nanocrystals (CNC) for the elaboration of biodegradable films. Different films have been formed by using WSH as a matrix and different contents of CNC and citric acid. The predominant hemicelluloses were arabinoxylans. CNC reinforced the films, improving tensile strength and modulus, water resistance and water vapor barrier. Citric acid, on the other hand, presented concomitant plasticizing and crosslinking effects (the latter also evidenced by FTIR), probably due to a crosslinking extension by glycerol. The use of 5.9wt% CNC and 30wt% citric acid was defined as optimal conditions, resulting in minimum water sensitivity and permeability, while maintaining a good combination of tensile properties. Under those conditions, the films presented enhanced modulus, elongation, water resistance, and barrier to water vapor when compared to the control WSH film, and might be used for wrapping or coating a variety of foods.

Recent Advances on Edible Films Based on Fruits and Vegetables-A Review.

Food packaging materials are traditionally expected to contain foodstuffs and protect them from deteriorating agents. Although petroleum-derived polymers have been widely used for this purpose, the rising concern with their nonrenewable and/or nonbiodegradable nature paves the route for the development of greener alternatives, including polysaccharides and polypeptides. The use of these food-grade biomacromolecules, in addition to fruits and vegetables, provides edible packaging with suitable physical-mechanical properties as well as unique sensory and nutritional characteristics. This text reviews the chronological development pathway of films based on fruit and vegetable purees, pomaces, and extracts. Recent advances are extensively reviewed with an emphasis on the role that each film component plays in the resulting materials, whose production methods are examined from a technical standpoint and essential properties are compiled and contrasted to their conventional, synthetic counterparts. Finally, this comprehensive review discusses advantages and limitations of edible films based on fruits and vegetables.

Pectin extraction from pomegranate peels with citric acid.

Pectins were extracted from pomegranate peels with citric acid, according to a central composite design with three variables: pH (2-4), temperature (70-90°C), and extraction time (40-150min). Fourier transform infrared (FTIR) spectroscopy was used to follow changes in material composition during the main steps of pectin extraction, and also to determine the degree of methyl esterification and galacturonic acid content of pectins produced under different conditions. Harsh conditions enhanced the extraction yield and the galacturonic acid contents, but decreased the degree of methoxylation. The optimum extraction conditions, defined as those predicted to result in a yield of galacturonic acid higher than 8g/100g while keeping a minimum degree of methoxylation of 54% were: 88°C, 120min, pH 2.5. Close agreement was found between experimental and predicted values at the extraction conditions defined as optimum.

Development of pectin films with pomegranate juice and citric acid.

The influence of pomegranate juice (PJ, replacing water as solvent) and citric acid (CA) on properties of pectin films was studied. PJ provided the films with a bright red color, and acted as a plasticizer. Increasing PJ/water ratio from 0/100 to 100/0 resulted in enhanced elongation (from 2% to 20%), decreased strength (from 10 to <2 MPa) and modulus (from 93 to <10 MPa), increased water vapor permeability (WVP, from 3 to 9 g.mm.kPa(-1).h(-1).m(-2)), and decreased insoluble matter (IM, from 35% to 24%). Although a crosslinking effect by CA was not confirmed, it has been suggested to occur from its effects on films. CA noticeably increased IM (from <10% to almost 40%); moreover, when measured on a dry film basis, the CA effects presented a noticeable tendency to increases strength and modulus, and to decrease WVP. The red color density was decreased by CA, suggesting a destabilization of anthocyanins.

Pomegranate peel pectin films as affected by montmorillonite.

The industrial production of pomegranate juice has been favored by its alleged health benefits derived from its antioxidant properties. The processing of pomegranate juice involves squeezing juice from the fruit with the seeds and the peels together, leaving a pomace consisting of approximately 73 wt% peels. In this study, pectin was extracted from pomegranate peels, and used to produce films with different contents of montmorillonite (MMT) as a nanoreinforcement material. The nanoreinforcement improved the tensile strength and modulus of films when added at up to 6 wt%, while the further addition of MMT (to 8 wt%) reduced the reinforcement effect, probably because of dispersion problems. The elongation was decreased with increasing MMT concentrations. The water vapor permeability decreased with increasing MMT contents up to 8 wt% MMT, indicating that the increased tortuosity of the permeant path was effective on barrier properties of the film.

Optimization of pectin extraction from banana peels with citric acid by using response surface methodology.

A central composite design was used to determine effects of pH (2.0-4.5), extraction temperature (70-90 °C) and time (120-240 min) on the yield, degree of methoxylation (DM) and galacturonic acid content (GA) of pectins extracted from banana peels with citric acid. Changes in composition during the main steps of pectin extraction were followed by Fourier transform infrared (FTIR) spectroscopy. FTIR was also used to determine DM and GA of pectins. Harsh temperature and pH conditions enhanced the extraction yield, but decreased DM. GA presented a maximum value at 83 °C, 190 min, and pH 2.7. The yield of galacturonic acid (YGA), which took into account both the extraction yield and the pectin purity, was improved by higher temperature and lower pH values. The optimum extraction conditions, defined as those resulting in a maximum YGA while keeping DM at a minimum of 51%, were: 87 °C, 160 min, pH 2.0.