Low Water Activity Research Articles

Ultrasound-assisted osmotic dehydration, followed by convective drying of papaya: effect on physicochemical and functional quality parameters

Papaya is a rich source of nutrients, antioxidants, and vitamins; however, it is highly perishable and hence needs to be preserved using suitable unit operations. Drying is an economical method of papaya treatment, but results in the loss of essential nutrients and also degrades its pigments, color, and texture. Therefore, this work aims to utilize ultrasound and osmotic dehydration as pretreatment strategies to preserve the rich composition of papaya during conventional hot air drying. The dried papaya slices were evaluated for moisture content, water activity, total phenolic content, β-carotene, color, antioxidant activity, microstructure, and texture. Results showed that sample pretreatment with 33 kHz ultrasound frequency and dehydrated with 35°Brix osmotic solution resulted in lower moisture content (< 12% w.b.) and water activity (< 0.41), high phenolic content (88.5 mg GAE/mL), high β-carotene content (184.54 mg/g) and antioxidant capacity (48.3%), and preserved color after drying. The texture (hardness) of the pretreated samples was also more desirable from an industrial standpoint, which was further validated using SEM micrographs that showed a more porous structure. The study concludes that pretreatment of papaya slices with ultrasound and osmotic dehydration is recommended before drying.

Obtention of Sacha Inchi (Plukenetia volubilis Linneo) Seed Oil Microcapsules as a Strategy for the Valorization of Amazonian Fruits: Physicochemical, Morphological, and Controlled Release Characterization.

Sacha inchi seed oil (SIO) is a promising ingredient for the development of functional foods due to its large amount of high-value compounds; however, it is prone to oxidation. This work aimed to obtain SIO microcapsules using conventional and ultrasound probe homogenization and using spray- and freeze-drying technologies as effective approaches to improve the long-term stability of functional compounds. The application of ultrasound probe homogenization improved the rheological and emulsifying properties and decreased the droplet size and interfacial tension of emulsions. The microcapsules obtained by both drying technologies had low moisture (1.64-1.76) and water activity (0.03-0.11) values. Spray-dried microcapsules showed higher encapsulation efficiency (69.90-70.18%) compared to freeze-dried ones (60.02-60.16%). Thermogravimetric analysis indicated that heat protection was assured, enhancing the shelf-life. Results suggest that both drying technologies are considered effective tools to produce stable microcapsules. However, spray-drying technology is positioned as a more economical alternative to freeze-drying.

Characterisation of a High Fibre Flour Prepared from Soy Milk By-Product and Its Potential Use in White Wheat Bread.

The commercial production of soy milk renders a large quantity of wet soybean by-product (SMB), which is typically dumped, incinerated, or partially used as animal fodder. This wet SMB has a high moisture content that is rich in nutritional and biologically active compounds. This study aimed to characterise the composition and properties of a flour milled from SMB dried at 100 °C (SMB100) and assess its possible application as a fibre substitute in white bread. The results showed that SMB100 has high levels of dietary fibre (40.6%) and protein (26.5%). It also contains high levels of saponins (31.4 mg/g) and isoflavones (698.0 µg/g). SMB100 has a light-yellow colour with low moisture content and water activity (8.2% and 0.55, respectively). The results also indicated that replacement of wheat flour with SMB100 at 10 or 12.5% by flour weight negatively impacted the raising volume, density, and texture of white bread. Alternatively, substituting wheat flour with 5% of SMB100, did not significantly impact the physical properties of white bread, while significantly improving its dietary fibre content in comparison with the control, revealing that SMB100 is a potential substitute of wheat flour for improvement of dietary fibre in bread. Future studies are needed to optimise bread formulation and improve the processing condition which produces quality white bread with high dietary fibre using SMB100.

Electrolyzed water and gaseous ozone application for the control of microbiological and insect contamination in dried lemon balm: Hygienic and quality aspects

In this study, the sanitization efficacy of decontamination techniques was evaluated on lemon balm (Melissa officinalis). Dried aromatic herbs are minor food components with widespread use and, despite their low water activity, they are often contaminated with microorganisms, including toxigenic and pathogenic ones. Gaseous ozone (GO) and electrolyzed water (EW) treatments were applied on lemon balm after and before drying (traditional at 40 °C and cold at 20 °C), respectively. Microbiological and entomological decontamination aspects were assessed as well as the sensory quality and compositional properties of the product in terms of essential oil, total polyphenol and ascorbic acid contents, and antioxidant capacity. The most interesting results concerned EW treatment (400 ppm × 1 min dipping) reducing aerobic mesophilic bacteria, Enterobacteriaceae, moulds and yeasts of about 4.0, 2.5, 2.0 and 1.0 Log cfu/g, respectively, thus below law limits. Moreover, 200 ppm EW x 1 min dipping was enough for limiting Bacillus cereus growth. However, sanitization against the beetle species Tribolium castaneum and Lasioderma serricorne was less efficient with EW (less than 40% mortality) compared with GO (200,000 ppm × min) (more than 95% mortality). Noteworthy, sensory analysis highlighted that lemon balm exposed to EW treatment did not lose organoleptic quality, in particular the color even seemed to improve in brightness when the herbs were subsequently cold dried. Furthermore, the loss in essential oils was not significant in terms of the overall content as well as total polyphenol, ascorbic acid and antioxidant capacity in EW treated lemon balm then submitted to cold drying. Differently, the combination of EW treatment and traditional drying led to a significant detriment of compositional properties. The results obtained in this study are encouraging and deserve to be discussed with producers.

Production and Quality Evaluation of Arabic Bread from Different Gluten-Free Flours

This study aims to produce gluten-free flatbread for Celiac Disease ( CD) patients from different gluten – free flour sources and compare its quality with that produced from wheat flour. Arabic flat pocket - former bread was prepared from the flours of wheat, corn, millet, buckwheat, quinoa, rice, potatoes, and tapioca using the straight dough method, and its physical quality parameters of specific volume, pocket formation, upper to lower layer ratio and water activity as well as sensory parameters of , freshness immediately and 4 hours after baking, and taste were evaluated.&#x0D; Proximate composition of the flours indicated that wheat flour had the highest protein content followed by corn, millet, quinoa, and buckwheat while rice, potatoes, and tapioca flours had the lowest protein content. Sensory and physical evaluation of the bread types showed that most flour types gave bread loaves with good specific volumes compared to wheat flour. Most bread types were tender when freshly baked, but only wheat and potato breads maintained their tenderness 4 hours after baking. The taste of potato and tapioca breads were the most acceptable and similar to that of wheat bread ( P≤0.05). It can be concluded that pocket-forming flatbread with good sensory and functional characteristics can be produced from most flours if consumed fresh after baking.

Characterization of eutectic mixtures of sugars and sugar-alcohols for cryopreservation

Natural Deep Eutectic Systems (NADES) composed of sugar and sugar alcohols have been studied and applied in a variety of biological applications. Understanding their interaction with water across dilution and temperature is inherently important for maximizing the utility of NADES. Herein a wide range of sugar:sugar-alcohol molar ratios were synthesized and characterized by viscosity, molar excess volume, differential scanning calorimetry, water activity, and confocal Raman cryomicroscopy. NADES were found to have greater viscosity, reduced heat of fusion, greater absolute molar excess volume, lower water activity, and stronger hydrogen bonding of water than non-NADES mixtures. This is hypothesized to be due to cumulatively stronger hydrogen bonding interactions between components in pure and diluted NADES with the strongest interactions in the water-rich region. This work provides useful data and further understanding of hydrogen bonding interaction strength for a wide range of molar ratios in pure to well-diluted forms.

Genes associated with desiccation stress in foodborne Staphylococcus aureus as revealed by transposon insertion mutagenesis

Staphylococcus aureus (S. aureus) is an opportunistic foodborne pathogen whose survival in food processing environments may be associated with its tolerance to desiccation. However, the molecular mechanisms involved in desiccation stress have received little attention in S. aureus. Here, some potential genes related to desiccation stress were determined in S. aureus by the transposon random mutagenesis approach. Eight mutants with different mutant sites who showed lower survival rates compared to wild-type (WT) strain RMSA24 under desiccation stress were successfully screened from a mutant library (n = 3,154). The eight mutation sites are identified as potential genes of U32 family peptidase, CHAP domain-containing protein, YdcF family protein, RNA polymerase sigma factor, EVE domain-containing protein, acetyltransferase, LPXTG-anchored DUF1542 repeat protein FmtB, and CvpA family protein, which haven’t been reported as the desiccation-tolerant related genes. We found that the growth rates and biofilm formation abilities of these mutants were not significantly affected, indicating that their reduced survival rates under desiccation stress not dependent on reduced growth rates and biofilm formation abilities. Under desiccation stress, the expression levels of the three mutated genes were up-regulated and the four mutated genes were down-regulated in the WT strain, implying that these genes may play different roles in S. aureus to adapt to desiccation stress conditions. The study reveals valuable information for the control of S. aureus in low water activity foods and their production environments.

Physical, Nutritional, and Bioactive Properties of Mandacaru Cladode Flour (Cereus jamacaru DC.): An Unconventional Food Plant from the Semi-Arid Brazilian Northeast.

In this study, we evaluated the physical, nutritional, and bioactive properties of mandacaru cladode flour (Cereus jamacaru DC.). The granulometric profile revealed particles with non-uniform geometry, flakiness, a rectangular tendency, and a non-homogeneous surface, with particle sizes ranging from 20 to 60 µm. The flour presented low water activity (0.423), a moisture content of 8.24 g/100 g, high ash (2.82 g/100 g), protein (5.18 g/100 g), and total carbohydrate contents (74.48 g/100 g), and low lipid contents (1.88 g/100 g). Mandacaru flour is an excellent source of insoluble dietary fiber (48.08 g/100 g), calcium (76.33%), magnesium (15.21%), and potassium (5.94%). Notably, 1H NMR analysis revealed the presence of N-methyltyramine. Using HPLC chromatography, glucose was identified as the predominant sugar (1.33 g/100 g), followed by four organic acids, especially malic acid (9.41 g/100 g) and citric acid (3.96 g/100 g). Eighteen phenolic compounds were detected, with relevant amounts of kaempferol (99.40 mg/100 g), myricetin (72.30 mg/100 g), and resveratrol (17.84 mg/100 g). The total phenolic compounds and flavonoids were 1285.47 mg GAE/100 g and 15.19 mg CE/100 g, respectively. The mean in vitro antioxidant activity values were higher using the FRAP method (249.45 µmol Trolox TEAC/100 g) compared to the ABTS•+ method (0.39 µmol Trolox TEAC/g). Finally, the ascorbic acid had a content of 35.22 mg/100 g. The results demonstrate the value of mandacaru as a little-explored species and an excellent matrix for the development of flours presenting good nutritional value and bioactive constituents with excellent antioxidant potential.

Evaluation of freeze-dried phenolic extract from cashew apple by-product: Physical properties, in vitro gastric digestion and chemometric analysis of the powders

The aim of this study was to produce powders from the phenolic extract of the cashew by-product using maltodextrin and gum arabic as encapsulating agents to preserve these bioactive compounds and their antioxidative activity. Extraction was assisted by an ultrasound bath to increase the release of the bioactive compounds, resulting in the hydroalcoholic extract from cashew bagasse. The powders were physically and morphologically characterized, and their total phenolics, antioxidant activity and bioaccessibility were evaluated. All parameters were analyzed by chemometrics. In addition, UPLC-HRMS analysis was used to evaluate the phenolic profile of the extracts, revealing that the powders were able to protect some of the original compounds of the extract, such as catechin, the myricetin fraction and quercetin. The powders showed high total phenolic retention capacity, especially maltodextrin (2893.34 ± 20.18 mg GAE/100 g (DW)), which was the encapsulant that preserved the highest content of polyphenols and antioxidant activity after bioaccessibility in comparison to the unencapsulated extract. The powders showed low water activity (<0.2), low moisture (<8%), high solubility (>60 %) and low hygroscopicity (<4%). The SEM analysis showed that lyophilized extract samples resembled broken glass, which is characteristic of the lyophilization process, and in addition to a predominantly amorphous structure as demonstrated by the X-ray diffraction. The extraction and encapsulation of phenolic compounds from the cashew by-product through lyophilization and using maltodextrin and gum arabic as encapsulants enabled their preservation and potential use of these compounds by the nutraceutical or food industry, and can be used as food additive in order to enrich the content of compounds and the antioxidant activity of numerous products.

Production and Characterization of Dehydrated Acerola Pulp: A Comparative Study of Freeze and Refractance Window Drying

Acerola is a perishable fruit with high vitamin C levels and an attractive nutrition property. The goal of the present work was to produce dehydrated acerola pulp with preserved vitamin C, selecting freeze-drying and refractance window (considered a novel and promising drying method) as suitable technologies. The final properties of dehydrated pulps using the drying technologies freeze-drying and refractance window were compared: i) water activity, ii)moisture content, iii) hygroscopicity, iv) color parameters, v) microstructure, vi) antioxidant activity, and vii) ascorbic acid stability (30 °C, 75% RH). The dried acerola pulps exhibited low moisture, water activity, and hygroscopicity regardless of the drying technology. However, the pulp dehydrated by refractance window presented significantly higher antioxidant activity than the freeze-dried pulp, with higher ABTS•+ (1,838.60 μM TE/g dehydrated pulp) and FRAP (1,290.00 μM TE/g dehydrated pulp) values. The ascorbic acid stability values were also higher for the pulp dried by the refractance window, which showed a final content of 98.03 mg/100 g dehydrated pulp after ten days of storage. The refractance window is a more appropriate technology to dehydrate acerola pulp with high vitamin C content, antioxidant activity, and ascorbic acid stability than freeze-drying.

Media impacts recovery of Salmonella enterica and Enterococcus faecium NRRL B2354 from whole black peppercorns, basil leaves, and chia seeds treated with antimicrobial gasses

Salmonella enterica contamination of low water activity foods (LWAFs) has resulted in recalls of spices, herbs, and seeds and outbreaks of salmonellosis. To improve the safety of these ready-to-eat products, new treatment methods, including fumigation with chlorine dioxide (ClO2) or hydrogen peroxide (H2O2) gas are being explored, and effectiveness determined. To prevent overestimation of treatment effectiveness, it is vital that recovery methods should accurately quantify all viable cells, even those injured. This study evaluated different media and supplements for the recovery of multiple strains of S. enterica and Enterococcus faecium NRRL B2354, from ClO2 or H2O2 treated black peppercorns, dried basil leaves, and chia seeds. Also, this study aimed to compare the log reduction of these two microorganisms to evaluate E. faecium NRRL B2354, as a surrogate for S. enterica. On average, recovery of S. enterica was improved by 1 log CFU from ClO2 and H2O2 treated LWAFs when a non-selective but differential media containing tryptic soy agar with yeast extract, ammonium iron citrate and sodium thiosulfate (MTSAYE) was used, when compared to plating on XLD (p &amp;lt; 0.05). Furthermore, addition of sodium pyruvate, ferrous sulfate, or 3’3’-thiodiproionate supplements to MTSAYE did not show increased recovery of either S. enterica or E. faecium NRRL B2354 (p &amp;gt; 0.05). On each treatment and LWAF combination tested, there was no significant difference between the log reduction of S. enterica and E. faecium NRRL B2354, indicating its suitability as a surrogate under the test conditions.

The Vacuum and Light-Avoided Packaging Ameliorate the Decline in Quality of Whole Chili during Storage

Vacuum packaging is a superior procedure that could maintain the quality of dried red peppers for a relatively longer period, while the effect of light avoidance was inconsistent. Therefore, this study was to evaluate the effect of vacuum in combination with light avoidance on the storage quality of peppers and to investigate vacuum packaging and vacuum and light-avoided packaging influence the quality characteristics of dried chili peppers during storage. The results indicated that the quality characteristics of peppers gradually deteriorated: redness, extractable color, capsanthin, capsaicinoids, pungency, total phenolic content, and antioxidant capacity decreased, whereas moisture, water activity, and browning index increased as storage progressed. Vacuum packaging inhibited these changes compared with the control. Vacuum and light-avoided packaging further decelerated the quality loss of dried peppers, with the minimum changes in color, pungency, and antioxidant capacity of dried peppers during storage, and these could be due to lower water activity by light avoidance. Therefore, light avoidance may be necessary to further delay the deterioration of dried peppers under vacuum, and vacuum and light-avoided packaging could better retain the quality of dried chili peppers.

Effect of drying methods on yield, physicochemical properties, and total polyphenol content of chamomile extract powder.

Chamomile (Matricaria chamomilla L.) is a traditional medicinal plant used to treat hay fever, inflammation, muscle spasms, menstrual disorders, insomnia ulcers, wounds, gastrointestinal disorders, rheumatic pain, and hemorrhoids. Dried chamomile flowers have a longer shelf life and the dried extract in form of powder offers much flexibility for new therapeutic formulations as it could be used as a replacement for liquid extract and serve as a shelf-stable ingredient in new applications. This study aims to determine the effect of drying methods, i.e., convection oven-drying at 45 °C, freeze-drying at -50°C, and spray-drying at 140°C at 10.5 and 12ml/min, respectively) on powder yield, physicochemical properties (moisture content, water activity, and color attributes), and total polyphenol content of chamomile extract powder. Our findings showed that spray-drying conducted at 140°C, 12ml/min resulted in the lowest yield of powder (16.67%) compared to convection oven-drying (90.17%) and freeze-drying (83.24%). Decreasing the feed flow rate to 10.5ml/min during spraying caused an increase in powder yield to 26.99%. The moisture content of spray-dried chamomile extract powder obtained at 140°C, 10.5ml/min was higher (11.00%) compared to that of convection oven-dried (8.50%) and freeze-dried (7.50%). Both convection oven-dried and freeze-dried chamomile extract powder displayed no significant difference (p > 0.05) in moisture content. The higher feed flow rate (12ml/min) in spray-drying also led to an increase in the moisture content of chamomile extract powder to 12.00%. The higher residual moisture found in the spray-dried samples resulted in partial agglomeration of particles. In terms of water activity, freeze-dried chamomile extract powder was found to have the highest water activity (0.63) compared to that of convection oven-dried (0.52), spray-dried at 140°C, 10.5ml/min (0.57), and spray-dried at 140°C, 12ml/min (0.58). Spray-dried and freeze-dried chamomile extract powder with high moisture content and water activity could be highly susceptible to microbial growth. In terms of color attributes, higher drying temperature in spray-drying led to darker, redder, and more yellowish chamomile extract powder that could be caused by heat-induced Maillard reaction and caramelization. Since lower drying temperature was used in both convection oven-drying and freeze-drying, both convection oven-dried (56.94mg GAE/g powder) and freeze-dried chamomile extract powder (55.98mg GAE/g powder) were found to have higher total polyphenol content compared to those of spray-dried (42.79-46.79mg GAE/g powder). The present findings allow us to understand the effect of drying methods on the properties of chamomile extract powder and provide a better drying option to dry chamomile extract. Due to higher powder yield with ideal powder properties such as low moisture content and water activity, desirable color, and high total polyphenol content obtained from convection oven-drying, convection oven-drying was a better option than freeze-drying and spray-drying for drying chamomile extract.

Microencapsulation of Phenolic Extract from Sea Grape (Coccoloba uvifera L.) with Antimutagenic Activity.

This study aimed to microencapsulate the sea grape ethanolic extract by the spray drying process, characterizing the obtained powder, and evaluating its antimutagenicity activity. Microparticles showed a mean size of 6.28 μm and a spherical shape with a smooth surface. The powder had a low moisture content (4.02±0.92 %) and water activity (0.27±0.01), and high solubility (76±3.60 %). Moreover, hygroscopicity (14.75±2.63 g/100 g of powder) and bulk density (0.63±0.03 g/cm3 ) values suggested that this powder can be easily handled at a pilot or industrial scale. In addition, microencapsulation protected the extract against oxidation by ultraviolet light, improved its thermal stability, and its antimutagenicity activity was similar to fresh sea grape extract. In conclusion, the microencapsulation with maltodextrin by spray drying technique is an alternative to protect bioactive compounds from sea grapes against environmental conditions, maintaining their antimutagenic activity.

Shelf Life of Greenhouse- and Garden-grown Kale in Nitrogen-enriched and Nonenriched Packaging

Over half of global food waste occurs in retail and households, highlighting the importance of improving shelf life. Many factors affect shelf life, including storage temperature, harvest time, processing method, and packaging. Modified atmosphere packaging (MAP), such as nitrogen (N2), has been used to improve the shelf life of produce. This study aimed to determine the effect of nitrogen-enriched packaging on the shelf life of greenhouse- and garden-grown kale in raised beds outdoors. Five kale cultivars (Black Magic, Darkibor, Lacinato, Red Russian, and Westlander) were grown in the greenhouse, and four cultivars (Curly Roja, Dwarf Green Curled, Meadowlark, and Vates) outdoors in raised beds, harvested and stored in nitrogen-enriched or nonenriched bags for 6 days. Leaf water content, water activity, color, visual score, and texture were measured for each replicate. Nitrogen-enriched packaging did not affect the kale shelf life. Garden-grown kale exhibited significantly lower water activity (0.979 vs. 0.999) and noticeably lower water content (88.6 vs. 90.6%) than greenhouse-grown kale. The cultivars were significant for all factors tested except for texture on day 4 and change in light to dark (Δ L*) and blue to yellow (Δ b*) color ratios. At the end of the study, cultivars Darkibor and Curly Roja had the highest visual score (4.4) and texture (305 g), respectively. The high performance of ‘Darkibor’ and ‘Curly Roja’ in visual score and texture may be due to decreased (Δ L*) and (Δ b*) values and decreased water content and water activity values. Future breeding efforts focused on the shelf life of kale should use the top-performing cultivars identified in this study and a diverse genetic population tested in a range of environments to develop cultivars with a longer shelf life.

Zn metal anodes stabilized by an intrinsically safe, dilute, and hydrous organic electrolyte

Rechargeable Zn batteries hold great promise for large-scale energy storage applications but their reversibility is limited by non-compact and dendritic Zn deposition along with interfacial parasitic reactions in conventional electrolytes. Herein, we report an intrinsically safe, dilute, and hydrous organic electrolyte by coupling hydrated Zn(BF4)2 salt with trimethyl phosphate (TMP) solvent for highly reversible Zn batteries, without the need of concentrated electrolyte strategies. The formulated 1 m Zn(BF4)2/TMP enables spatially compact, dendrite-free, and corrosion-free Zn electrodeposition even at high areal capacity (5 and 10 mAh cm−2) using a pressure-free electrolytic cell. Moreover, the hydrous organic electrolyte with low water activity expands the electrochemical window to 3 V (versus Zn2+/Zn) and in-situ forms a protective ZnF2-Zn3(PO4)2-rich interphase on Zn. The resultant Zn electrode achieves long-term cycling over 4200 h with a superhigh cumulative plating capacity of 10500 mAh cm−2 under 5 mA cm−2 in Zn//Zn cell and exhibits high efficiency of 99.5% over 600 cycles in Zn//Cu cell (1 mA cm−2; 1 mAh cm−2). Moreover, this electrolyte supports the stable operation of a full Zn//V2O5·nH2O battery by significantly suppressing cathode dissolution. This work would enlighten the design of hydrous organic electrolytes for practical Zn batteries.

Green Coffee Extract Microencapsulated: Physicochemical Characteristics, Stability, Bioaccessibility, and Sensory Acceptability through Dairy Beverage Consumption.

This study aimed to investigate the effect of spray drying (SD) and freeze-drying (FD) on the microencapsulation of green coffee extracts by using polydextrose (PD) and inulin (IN) as encapsulating agents and their physicochemical, bioactive compounds’ stability, phenolic compounds’ bioaccessibility after digestion, and sensory effects in unfermented dairy beverages. The extract encapsulated with IN by FD had lower moisture content, water activity, and hygroscopicity, while particles encapsulated by SD exhibited a spherical shape and the structure of the FD products was irregular. No difference was observed in phenolic compounds’ bioaccessibility. Dairy beverages with added encapsulated extracts had higher total phenolic content and antioxidant activity. Microencapsulation allowed a controlled release of the bioactive compounds with an increase in the content of caffeine, chlorogenic acid, and trigonelline during storage. The dairy beverage with added extract encapsulated with IN by FD had the highest scores of acceptability regarding the overall impression and purchase intent.

Single and combined use of isomalt, polydextrose, and inulin as sugar substitutes in production of pectin jelly

In this study, 60% of the total sugar (sucrose and corn syrup) in pectin jellies was substituted by using single or various combinations of the bulking agents: isomalt, polydextrose, and inulin. Substitution with isomalt resulted in lower hardness and flexibility and lower moisture content; it ended up with an opaque and rough appearance on the outer surface, thus causing lower sensory acceptability and shorter storage stability than conventional product. Substitution of sugars with inulin was found to be successful in terms of lowering water activity, improving sensory characteristics, and supporting the prebiotic activity (B. clausii). Polydextrose was also successful, while bringing with the handicap of a softness perception in the jelly due to high hygroscopicity. Besides, it was the most effective bulking agent for growth of both the beneficial probiotic bacteria tested (Lactobacillus acidophilus and Bacillus clausii). The highest colony counts of L. acidophilus was found in Inulin+Polydextrose jelly (220 × 104 CFU/g); however, this synergistic effect of inulin and polydextrose was not observed for B. clausii. Substitution of sugars with only inulin gave the best results for taste, at the same time scored high for color and appearance. In relation to this, 90% of panelists preferred the inulin jelly as “I would definitely buy.” The lowest energy values were achieved in jellies developed by the addition of polydextrose, inulin+polydextrose, and isomalt+polydextrose with 43.1% 39.9%, and 38.8% reductions in calorie, respectively, compared with the conventional product. The results demonstrated many aspects of the successful use of polydextrose and inulin alone or in combination as sugar substitutes in the production of pectin jelly. Practical applications The awareness for the consumption of functional foods, which contain ingredients that provide additional health benefits beyond the basic nutritional requirements, is in increasing demand. In order to meet this demand of consumers, nutritious, functional, and alternative foods have started to take their place in the market. Confectionery products have an important place among these food groups. As a market that has consumers from all age groups apart from basic nutritional needs, the confectionery sector has a diverse product group and large consumer base in the world. Prebiotics are included in confectionery products in order to give mouthfeel, texture, functional attributes, and some act as bulking agent. We investigated the combined use of prebiotics such as polydextrose, inulin, and isomalt as bulking agents in soft pectin jellies, and significant improvement was achieved in terms of low-energy product development. The low-energy soft-type pectin jellies were characterized, and the samples using prebiotics showed various advantages in terms of physical properties.

Encapsulation of Bilberry Extract with Maltodextrin and Gum Arabic by Freeze-Drying: Formulation, Characterisation, and Storage Stability

Anthocyanins are polyphenolic plant pigments associated with antioxidant and health-promoting properties. However, their application in the food industry is limited due to their poor stability. The purpose of this study was to encapsulate anthocyanin-rich bilberry (Vaccinium myrtillus L.) extract by freeze-drying and to investigate the effects of different wall materials and extract contents on the physicochemical and bioactive properties of the obtained encapsulates. Ethanolic bilberry extract was encapsulated with the use of maltodextrin (16.5–19.5 DE) (MD), gum Arabic (GA), and their combination in a 1:1 w/w ratio (MIX). Bilberry solids to wall material ratios were examined at 20:80, 30:70, and 40:60. All encapsulates showed an attractive red colour and low water activity values (aw ≤ 0.3) that indicated a low risk of microbial spoilage. In general, the biggest losses of total phenolic compounds and anthocyanins during three-week storage in the dark and at room temperature (20 ± 2 °C) were detected in the case of encapsulates with a higher content of bilberry extract (MIX30 and MIX40, and GA30 and GA40, respectively). The use of maltodextrin provided the best protection to bilberry anthocyanins during forced storage. Overall, the obtained encapsulates show suitable potential for the development of food products with added nutritional benefits.

Thermal Inactivation of Salmonella enterica and Nonpathogenic Bacterial Surrogates in Wheat Flour by Baking in a Household Oven

Wheat flour has been implicated in recalls and outbreaks linked to Salmonella and pathogenic Escherichia coli. An instructional online video posted on a popular YouTube channel with over 20 million subscribers claimed that safe raw cookie dough could be made from flour baked in a household oven at 177°C (350°F) for 5 min, but no evidence in support of that claim was provided. This study was conducted to assess thermal inactivation of two Salmonella strains, as well as Enterobacter aerogenes and Pantoea dispersa in wheat flour during home oven baking. Wheat flour was inoculated with Salmonella Enteritidis PT 30, Salmonella Typhimurium PT 42, or their potential surrogates at high concentrations (4.8 to 6.1 log CFU/g) before baking in a consumer-style convection oven (toaster oven) at 149, 177, and 204°C (300, 350, or 400°F) for up to 7 min. Flour was heated in an aluminum tray, with a maximum depth of ∼2 cm. Heated wheat flour samples (5 g each) were enumerated in triplicate, and the microbial concentration was expressed in log CFU per gram. Thermal profiles of the geometric center of the wheat flour pile and air in the oven during the baking were recorded. Water activity of wheat flour samples was also measured before and after baking. The water activity of wheat flour decreased, as baking temperature and time increased. Water activity values ranged from 0.30 to 0.06 after 7 min, as oven temperature increased from 149 to 204°C. Thermal inactivation kinetics were linear until counts approached the limit of detection for all microorganisms. D-values for Salmonella and potential surrogate strains ranged from 1.86 to 2.13 min at 149°C air temperature, 1.66 to 1.92 min at 177°C air temperature, and 1.12 to 1.38 min at 204°C air temperature. Both Salmonella strains and surrogates showed similar inactivation patterns. Baking of wheat flour in household toaster ovens has potential as an inactivation treatment of pathogenic bacteria in consumer homes, despite its low water activity.