Technological development and functional properties of an apple snack rich in flavonoid from mandarin juice

Investigating the potential of yacon (Smallanthus sonchifolius) juice in the development of organic apple-based snacks

This study investigates the potential of yacon (Smallanthus sonchifolius) juice for the development of prebiotic-rich organic apple-based snacks. Yacon syrup, primarily composed of fructan, inulin, fructooligosaccharides (FOS), and free sugars, represents a promising nutraceutical product. Its great potential in food processing, particularly as an innovative source of prebiotics, has been demonstrated both in vitro and in vivo since it is fermented specifically by lactobacilli and bifidobacteria. Our objective was to explore the feasibility of employing vacuum impregnation process to incorporate yacon juice into organic apples, followed by hot air drying for the formulation of dried organic apple-based snacks with health-enhancing attributes. We assessed the prebiotic and physicochemical characteristics of the impregnated snacks, also considering 50 days of storage at room temperature. Vacuum impregnation and air drying produced dried apple slices impregnated with yacon juice with good quality and stability. Higher levels of fructan (16-fold difference compared to non-impregnated apples) in the apple slices increased their prebiotic potential, promoting the growth and viability of cells within simulated intestinal fluid, including strains of Bifidobacterium animalis subsp. lactis BB -12, Bifidobacterium breve DSM 20091, Bifidobacterium longum subsp. infantis DSM 20088, Lacticaseibacillus rhamnosus GG and Lacticaseibacillus rhamnosus C112, even after prolonged storage. Remarkably, the physicochemical parameters of the impregnated and dried apple slices remained nearly constant and akin to the control samples. Therefore, the combination of vacuum impregnation and air drying has the potential to be used to produce enriched prebiotic organic apple snacks, providing consumers with additional health benefits, including enhanced gut health, with its associated implications, and increased satiety. This innovation could contribute to the development of health-promoting food products with improved nutritional profiles.

Assessment of ultrasound-assisted vacuum impregnation as a method for modifying cranberries' quality

Combined vacuum impregnation and ultrasound was proposed as an alternative method to improve the infusion of ascorbic acid in berry fruit. The effect of ultrasound application at different stages of impregnation - vacuum, relaxation, and both stages - on the qualitative characteristics of impregnated cranberries was investigated. The quality assessment was based on porosity, color, antioxidant capacity, anthocyanin, polyphenol and structure compound content. Ultrasound-assisted vacuum impregnation contributed to higher ascorbic acid content, smaller relative color difference, and greater antioxidant properties. It was found that the degree of impregnation varies considerably and depends on the stage of using ultrasound. Due to more favorable quality attributes, the conclusion was reached that ultrasound should be applied during the relaxation stage of vacuum impregnation.

Study of Water Distribution, Textural and Colour Properties of Cold Formulated and Air-Dried Apple Snacks

Vacuum impregnation is considered a cold formulation technology since it allows the incorporation of a desired functional compound into porous plant tissue without applying any heat. It is widely used in combination with the drying process to obtain added-value snacks. The aim of this work was to evaluate the effect of two trehalose concentrations (5 and 10% w/w) on: (i) the water state and texture evolution during the air drying (50 °C, 8 h) of apple snacks vacuum impregnated with blueberry juice, and on (ii) the colour of the final dried apple snacks. The results of nuclear magnetic resonance (NMR) showed that trehalose affects the water mobility of the samples during drying especially after 200–300 min of drying. In terms of textural properties, trehalose could increase the crispier characteristic of the samples impregnated with trehalose at the end of drying. Significative changes were found in terms of chroma and hue angle.

Potential Use of Vacuum Impregnation and High-Pressure Homogenization to Obtain Functional Products from Lulo Fruit (Solanum quitoense Lam.)

Lulo (Solanum quitoense Lam.) is a Colombian fruit that is mostly used in the preparation of homemade juice as well as natural remedy for hypertension. The aim of this study was to determine physicochemical and antioxidant properties (antioxidant capacity, total phenols, flavonoids and spermidine content, and polyphenolic compounds profile by liquid chromatography-mass spectrometry (LC-MS)) of the lulo fruit and its juice. Additionally, vacuum impregnation (VI) properties of the fruit and the effect of high homogenization pressure (50, 100, and 150 MPa) on the juice properties were studied. The results revealed a good availability and impregnation capacity of the pores in fruits with similar maturity index. The main differences observed between the juice and fruit derive from removing solids and bioactive components in the filtering operation. However, the effect of high-pressure homogenization (HPH) on particle size and bioactive compounds increases the antiradical capacity of the juice and the diversity in polyphenolics when increasing the homogenization pressure.

Comparing Three Types of Mandarin Powders Prepared via Microfluidic-Jet Spray Drying: Physical Properties, Phenolic Retention and Volatile Profiling

This study aimed to offer an alternative way for delivering the benefits of the mandarin fruit juice to consumers via spray drying microencapsulation. Two mandarin cultivars, Afourer (A) and Richard Special (RS), were studied. Three types of juice sample were prepared, i.e., the whole fruit juice (A3 & RS3), the flavedo-removed fruit juice (A2 & RS2), and the peel-removed fruit juice (A1 & RS1) samples. Gum Acacia and maltodextrin (ratio of 1:1, w/w) were chosen as wall matrices for aiding the drying of the juice samples while using a microfluidic-jet spray dryer. The properties of the fruit powder (colour, water activity, bulk/trapped density, solubility, hygroscopicity, morphology) and the retention of major phytochemicals (i.e., phenolic and volatile compounds) were examined. The results showed that the powders produced from the whole fruit juices (A3 and RS3) gave higher yellow colour with a regular winkled surface than other powders (A1 & RS1, and A2 & RS2). The water activity of mandarin powders was in a range of 0.14 to 0.25, and the solubility was around 74% with no significant difference among all of the powders. The whole fruit powders had a significantly higher concentration of phenolic compounds (A3, 1023 µg/100 mg vs. A2, 809 µg/100 mg vs. A1, 653 µg/100 mg) and aroma compounds (A3, 775,558 µg/L vs. A2, 125,617 µg/L vs. A1, 12,590 µg/L). This study contributed to the delivery of phenolic and flavour compounds of the mandarin fruits, at the same time minimising waste generation during processing. It also gave insight into the production of spray-dried powders from the whole mandarin fruits.

Survival of Lactobacillus salivarius CECT 4063 and Stability of Antioxidant Compounds in Dried Apple Snacks as Affected by the Water Activity, the Addition of Trehalose and High Pressure Homogenization

Survival of probiotic microorganisms in dried foods is optimal for water activity (a_w) values between 0.1 and 0.3. Encapsulating and adding low-molecular weight additives can enhance probiotic viability in intermediate a_w food products, but the effectiveness of sub-lethal homogenization is still not proven. This study evaluates the effect of 10% (w/w) trehalose addition and/or 100 MPa homogenization on Lactobacillussalivarius CECT 4063 counts and antioxidant properties of apple slices dried to different water activity values (freeze-drying to a a_w of 0.25 and air-drying at 40 °C to a a_w of 0.35 and 0.45) during four-week storage. Optical and mechanical properties of dried samples were also analyzed. Freeze-drying had the least effect on the microbial counts and air drying at 40 °C to a a_w of 0.35 had the greatest effect. Antioxidant properties improved with drying, especially with convective drying. Decreases in both microbial and antioxidant content during storage were favored in samples with higher water activity values. Adding trehalose improved cell survival during storage in samples with a water activity of 0.35, but 100 MPa homogenization increased the loss of viability in all cases. Air-dried samples became more translucent and reddish, rather rubbery and less crispy than freeze-dried ones.

Low-moisture food matrices as probiotic carriers

To exert a beneficial effect on the host, adequate doses of probiotics must be administered and maintaining their viability until consumption is thus essential. Dehydrated probiotics exhibit enhanced long-term viability and can be incorporated into low-moisture food matrices, which also possess high stability at refrigeration and ambient temperature. However, several factors associated with the desiccation process, the physicochemical properties of the matrix and the storage conditions can affect probiotic survival. In the near future, an increased demand for probiotics based on functionally dominant members of the gut microbiome ('next-generation probiotics', NGP) is expected. NGPs are very sensitive to oxygen and efficient encapsulation protocols are needed. Strategies to improve the viability of traditional probiotics and particularly of NGPs involve the selection of a suitable carrier as well as proper desiccation and protection techniques. Dehydrated probiotic microcapsules may constitute an alternative to improve the microbial viability during not only storage but also upper gastrointestinal tract passage. Here we review the main dehydration techniques that are applied in the industry as well as the potential stresses associated with the desiccation process and storage. Finally, low- or intermediate-moisture food matrices suitable as carriers of traditional as well as NGPs will be discussed.

Enrichment of Apple Slices with Bioactive Compounds from Pomegranate Cryoconcentrated Juice as an Osmodehydration Agent

Pomegranate juice is an important source of bioactive compounds, and cryoconcentrated juice is an interesting osmodehydration agent to enrich a vegetal matrix. This investigation aimed to incorporate bioactive compounds from pomegranate cryoconcentrated juice into apple slices using osmodehydration (OD) assisted by pulse vacuum (PV) and ohmic heating (OH). The apple slices (3 × 4 × 0.5 cm) were osmodehydrated using a 47 °Brix pomegranate cryoconcentrated juice at 30, 40, or 50°C for 180 min with an electric field of 6.66 V/cm (50 V) and a 5 min pulsed vacuum. Over the time, all of the treatments applied to the apple slices increased the soluble solids and bioactive compounds compared with the fresh sample. PVOD/OH at 50°C had the highest content of total anthocyanin during processing, and the best results for the total flavonoids were obtained with OD/OH at 50°C and 40°C. The osmodehydration assisted by pulse vacuum and ohmic heating using a cryoconcentrated juice is a useful combined technique to acquire enriched vegetal samples with bioactive compounds.

An Integrated Approach to Mandarin Processing: Food Safety and Nutritional Quality, Consumer Preference, and Nutrient Bioaccessibility

Mandarins are a member of the Citrus genus and are the focus of growing commercial interest, with satsuma mandarins (Citrus unshiu) and the common mandarin (Citrus reticulata Blanco) being the most important mandarin varieties. The possible health benefits and functional properties of those fruits are often associated with the antioxidative function of vitamin C, carotenoids, and phenolic compounds. While most mandarins are consumed fresh, many are processed into juices (mostly cloudy), usually via thermal processing which can lead to the creation of off-flavors and may diminish nutritional quality. The aim of this review is to summarize the most significant and recent information on the safety, sensorial properties, and nutritional benefits of mandarins and their processing into juice. The article also discusses recent information regarding the bioaccessibility of valuable, mandarin specific, compounds.

Apple snack enriched with L-arginine using vacuum impregnation/ohmic heating technology

Modern life has created a high demand for functional food, and in this context, emerging technologies such as vacuum impregnation and ohmic heating have been applied to generate functional foods. The aim of this research was to enrich the content of the semi-essential amino acid L-arginine in apple cubes using vacuum impregnation, conventional heating, and ohmic heating. Additionally, combined vacuum impregnation/conventional heating and vacuum impregnation/ohmic heating treatments were evaluated. The above treatments were applied at 30, 40 and 50  ℃ and combined with air-drying at 40 ℃ in order to obtain an apple snack rich in L-arginine. Both the impregnation kinetics of L-arginine and sample color were evaluated. The impregnated samples created using vacuum impregnation/ohmic heating at 50 ℃ presented a high content of L-arginine, an effect attributed primarily to electropermeabilization. Overall, vacuum impregnation/ohmic heating treatment at 50 ℃, followed by drying at 40 ℃, was the best process for obtaining an apple snack rich in L-arginine.

Applicability of vacuum impregnation to modify physico-chemical, sensory and nutritive characteristics of plant origin products--a review

Vacuum impregnation is a non-destructive method of introducing a solution with a specific composition to the porous matrices of fruit and vegetables. Mass transfer in this process is a result of mechanically induced differences in pressure. Vacuum impregnation makes it possible to fill large volumes of intercellular spaces in tissues of fruit and vegetables, thus modifying physico-chemical properties and sensory attributes of products. This method may be used, e.g., to reduce pH and water activity of the product, change its thermal properties, improve texture, color, taste and aroma. Additionally, bioactive compounds may be introduced together with impregnating solutions, thus improving health-promoting properties of the product or facilitating production of functional food.

Dried apple enriched with mandarin juice counteracts tamoxifen-induced oxidative stress in rats

The effect of a product made of dehydrated apples enriched with mandarin juice by vacuum impregnation on markers of oxidative stress (plasma antioxidant capacity, carbonyl groups (CGs), 8-hydroxydeoxyguanosine (8OHdG) and α-tocopherol) was tested in rats. Six groups of animals were studied: one group was fed a standard diet; two groups were supplemented with dehydrated apple either impregnated or not with mandarin juice throughout 28 days; and three groups (one unsupplemented and two supplemented) were additionally treated with tamoxifen (TAM) for 21 days used for induction of oxidative stress. The rats treated with TAM showed an increase in aminotransferases, CGs and 8OHdG. All of these effects were significantly decreased in the animals after apple snack consumption; the addition of mandarin juice into the apple mainly accounts for increased levels of α-tocopherol in plasma and liver. These findings suggest that the food product have a protective action against oxidative stress induced by TAM in rats.