Sonication Effect on Bioactive Compounds of Cashew Apple Bagasse

This study describes some effects of high-power ultrasound on cashew apple bagasse. The main objective was to develop an optimized process for sonication of cashew apple bagasse, evaluating the effect of ultrasound on antioxidant compounds. To define the best conditions for sonication, a 2³ factorial central composite design was used changing the independent variables: bagasse/water ratio, ultrasonic power intensity (W/cm²), and processing time (min). Antioxidant compounds such as vitamin C, β-carotene, and total phenolic compounds were determined. The total antioxidant capacity (ABTS(2,2 AZINO BIS (3-ethylbenzo thiazoline 6 sulfonic acid) diammoninum salt and DPPH (2,2-Diphenyl-1-picryl-hidrazil)) was also evaluated. A thermal treatment was carried at the highest temperature reached after sonication (51 °C) to evaluate the heat effect due to a temperature increase during processing. Sonication changed the bagasse aspect from a fibrous residue to a pleasant yellow puree. The maximal concentration of vitamin C, phenolics, and β-carotene was obtained when the processing conditions were as follows: bagasse/water ratio of 1:4 (w/w), ultrasound power intensity of 226 W/cm², and 6 min of processing. The high total phenolic content (2186 mg of gallic acid/100 g DW), vitamin C (148 mg/100 g DW), and β-carotene (12 mg/100 g) obtained proved the sonication efficiency. The antioxidant activity determined by the DPPH and ABTS assays confirmed the suitability of ultrasound for the preparation of antioxidant-rich cashew apple bagasse puree.     

Osmodehydration assisted by ohmic heating/pulse vacuum in apples (cv. Fuji): retention of polyphenols during refrigerated storage

Apples are a widely consumed fruit and have a high polyphenol content. The aim of this study was to analyse the combined effects of osmotic dehydration (OD) and ohmic heating (OH) with a pulsed vacuum (PV) on polyphenol retention during the stored refrigeration of apple cubes. Treatments were performed using a 65°Brix sucrose solution at 30, 40 or 50 °C for 120 min, and then, samples were stored for 28 days at 5 °C. OH provides an electric field of 13 V cm^?1, and a pulsed vacuum was applied for 5 min at the beginning of the process. The results indicated that a lower temperature process (30–40 °C) resulted in the retention of more polyphenol compounds after treatment than a higher temperature process (50 °C). Nevertheless, during refrigerated storage, we observed that 50 °C preserved these compounds better due to polyphenol oxidase inactivation. PVOD/OH treatment at 50 °C was determined to be the best retention of polyphenols from the fresh apple for dehydrating apples.     

Water Diffusion and Concentration Profiles During Osmodehydration and Storage of Apple Tissue

The objective of this work was to study the mobility of water and sucrose during osmotic dehydration and storage of apple tissue and to conduct an analysis of the behavior of the effective diffusion coefficients determined from concentration profiles. Osmotic dehydration (OD) of apple was carried out at 40°C for 1 h, and the solution: sample ratio was 20:1 (w/w). Samples of 20-mm diameter were extracted from the dehydrated apple immediately after the OD process and after 4 and 24 h of storage at 25 °C. Moisture of these samples and soluble solids content were analyzed. Our results showed, after 1 h of OD, the outer layer of the apple sample lost 0.37 kg water/kg apple and gained 0.30 kg sucrose/kg apple. These values decreased toward the internal layers of the apple. A fine layer of greatly dehydrated cells was formed on the surface around the sample, which determined the mass transfer rate in the whole tissue. Smaller mass transport rates were observed in the development of concentration profiles during storage. Diffusion coefficients obtained for the outer layer after 1 h of OD were 1.53 × 10⁻¹⁰ and 1.05 × 10⁻¹⁰ m²/s for water and sucrose, respectively. The analysis of compositional profiles developed during osmodehydration was a useful tool to get a better understanding of the changes in the water activity of the outer layer of the apple tissue.     

Effects of Ultrasound Assistance on Dehydration Processes and Bioactive Component Retention of Osmo‐Dried Sour Cherries

Despite having numerous health benefits, dried sour cherries have proven to be more acceptable to consumers when infused with sugar or other sweeteners to enhance their flavor, which, in turn, leads to serious anthocyanin losses. For this reason, a consideration was made for the application of ultrasound to accelerate solid gain and shorten drying time, thus favoring bioactive component retention. To determine the usefulness of ultrasound as a tool for sour cherry osmotic infusion enhancement, the effect of sonication time on dehydration effectiveness, as well as the stability of bioactive components during osmotic treatment and consecutive convective drying, was investigated. Fruits were osmo‐dehydrated using a 60% sucrose solution for 120 min (40 °C), during which, ultrasound of 25 kHz (0.4 W/cm²), was applied for 0, 30, 60, 90, and 120 min, after which, the fruits were convectively dried. In the range of the applied ultrasound energy no significant effect of sonication on mass transfer intensification was observed; moreover, longer acoustic treatment seemed to retard moisture removal during subsequent convective drying, which can be related to the breakdown of the parenchyma cell walls caused by the prolonged ultrasound (US) action. It was concluded that although US assistance could be considered neutral for bioactive component retention, excessive sonication time can lead to some anthocyanin deterioration. According to high‐performance liquid chromatography analysis, the particular anthocyanin alterations, both during dehydration and final drying, occurred in a similar way. Sonication time prolongation caused approximately 10% more bioactive compound deterioration, than earlier, shorter trials.     

Stability of Apple Polyphenols as a Function of Temperature and pH

The effect of heat treatment on apple polyphenols was investigated at six different temperatures over three different lengths of time. Apple polyphenols, after heat treatment, maintained similar concentrations in solution compared to the control (at room temperature). The effect of pH on apple polyphenols was investigated at 11 different pH levels and at 2 different temperatures. The pH-optimum for apple polyphenols proved to be 5.0. Two apple polyphenol concentrations, three vitamin C concentrations, two sugar concentrations, and two different temperatures were chosen to investigate the effect of apple polyphenols on vitamin C. Apple polyphenols showed good stability and can be used in many types of food products.     

Comparison of Effect of Gear Juicer and Colloid Mill on Microstructure,Polyphenols Profile,and Bioactivities of Mulberry (<Emphasis Type="Italic">Morus indica L</Emphasis>.)

Mulberry (Morus indica L.) fruits are rich sources of polyphenols with multiple health benefits. The gear juicer and colloid mill were compared in mulberry juice production and further marc water extraction based on polyphenol yield, phytochemical profiles, bioactivities, as well as microstructure of residues. Higher content of phenolic compounds, stronger antioxidative, and α-Glucosidase inhibition activities were obtained in colloid mill-processed juice. The extraction kinetics of marc was investigated under three conditions (stirring, ultrasound, and combined stirring and ultrasound) at 25 °C for 2.5 h. Based on total polyphenol and monomeric anthocyanin yield, the optimum extraction condition for gear juicer marc was combination of ultrasound with stirring for half an hour. While ultrasound for 1 h was optimized for water extraction of colloid mill marc. Using the optimized extraction condition, total polyphenols and monomeric anthocyanin obtained from colloid mill-processed samples, including juice and marc extract, were approximately 46 and 68 % higher than those in gear juicer-processed samples. Compared to gear juicer, colloid mill processing generated smaller particle size and more disrupted microstructure, which contributed to higher content of phenolic compounds in colloid mill juice. Moreover, changes in the microstructure of mulberry marc were intensified by extraction conditions, which improved polyphenol extraction efficiency, especially for colloid mill marc. These results provided valuable information for comparing gear juicer and colloid mill in mulberry as well as other berries for juice production and marc water extraction, and emphasized the great potential of colloid mill in berry processing.     

The Influence of Selected Osmotic Dehydration and Pretreatment Parameters on Dry Matter and Polyphenol Content in Highbush Blueberry (Vaccinium corymbosum L.) Fruits

The paper presents an assessment of the influence of selected highbush blueberry pretreatment methods and parameters on the process of osmotic dehydration conducted in 65 °Brix sucrose solution for 5 to 240 min at 30–70 °C. The pretreatment methods used included: fruit immersion in boiling water (15 s) and in 0.5 % NaOH solution (15 s at 95 °C), exposure to ultrasound at atmospheric pressure (vibration frequency of 35?±?5 kHz, 500 W, for 15 min.) and at low pressure (0.92 kg?cm^?1), and enzymatic processing; pectinase (enzyme activity of 46,000 PGU/mL; 0.6 mL/90 g of fruits; 30 min at approx. 22 °C) and lipase (enzyme activity of 750 PGU/mL; 0.7 mL/90 g of fruits; 30 min at approx. 22 °C) were used. Dehydration was also conducted in the presence of pectinolytic enzymes. The dehydrated material was analyzed in terms of the content of dry matter, total polyphenols, and particular polyphenols using high performance liquid chromatography. It was observed that dehydration was much more intensive at 60 and 70 °C, but such temperatures led to substantial losses of phenolic compounds (by 15–30 % after 2-h dehydration) and unfavorable changes in the texture of the final product. A promising method of pretreatment is fruit immersion in solutions containing pectinolytic and lipolytic enzymes, which increase dry matter content by 26 % (after 1 h of dehydration at 30 °C) with a low loss of phenolic compounds (4 %). Among the identified anthocyanins, the greatest retention during dehydration at various temperatures was displayed by petunidin-3-galactoside (over 80 % after 1 h of dehydration) and petunidin-3-glucoside (over 78 %).     

Effect of Selected Pretreatments on Impregnation of Curcuminoids and Their Influence on Physico-chemical Properties of Raw Banana Slices

The effect of pretreatments, namely, blanching, ultrasound, vacuum and their combinations on curcuminoid impregnation in raw banana slices, was studied in conjunction with treatments in pure water as well as in 10 % NaCl solution. The treatments such as ultrasound, vacuum and combination of vacuum and blanching with ultrasound resulted in higher curcuminoid infusion compared to control for both pure water and 10 % NaCl osmotic treatments. The blanching treatment resulted in lower infusion of curcuminoids as compared to that of control due to the gelatinisation of starch present in banana. Further, the increase in surrounding solution concentration from pure water to 10 % NaCl resulted in enhanced curcuminoid infusion (e.g. from 85 to 95 mg/100 g for combined vacuum and sonication treatment). However, the direction of the mass transfer of water as well as solid was reversed. The samples subjected to combined vacuum and sonication treatment resulted in lowest compressive force, highest infusion of curcuminoids and highest total colour difference compared to other treatments. Besides, the dehydration of such product also resulted in the highest retention of curcuminoids compared to the individual treatments. The present study concluded that osmotic treatment can be a feasible technology for the infusion of functional ingredients into foods without altering its matrix. The extent of infusion can be significantly enhanced by the application of combined treatment such as vacuum and ultrasound.     

Influence of ultrasound on the microstructure of plant tissue

The aim of this work was to assess the influence of ultrasound on the microstructure of plant tissue during direct sonication via air (without liquid medium). Two different materials (apple and onion) were tested under two experimental conditions: direct sonication in an acoustic chamber and convective drying enhanced with ultrasound in a laboratory hybrid dryer. The impact of ultrasound on the material being processed was analyzed through direct observation with the naked eye, analysis of thermograms, and observation of dyed in Lugol's solution specimens, using an inverted optical microscope and SEM images. The results obtained revealed both the thermal and the mechanical effects of ultrasonic action. The temperature of the materials processed with the use of ultrasound attained values higher than the temperature of ambient air, even during convective drying at 313 K. Moreover, application of ultrasound led to irreversible changes in structure (growth of porosity, loss of tissue coherence, formation of microchannels, etc.) and cell composition (destruction of cell components, e.g., the nucleus). Aberrations in cell walls or cell membranes due to ultrasonic passage were not observed. Explanations of the observed phenomena were proposed.     

Comparison of Antioxidant Activities and High-Performance Liquid Chromatography Analysis of Polyphenol from Different Apple Varieties

Concentration of polyphenols in apples depends on factors such as harvest, cultivar, processing, and storage conditions. We aimed to identify essential polyphenols present in various apple varieties, and measure their free phenol and antioxidant capacities using 1,1-diphenyl-2-picylhydrazyl radical scavenging capacity, oxygen radical absorbance capacity, hydroxyl radical scavenging capacity, and ferric reducing antioxidant power methods, and correlating with the total polyphenol content and antioxidant capacity with high-performance liquid chromatography results. Thirteen apple varieties cultivated in northwest China showed significant polyphenol content. Hongxun 1 had the highest polyphenol content and antioxidant capacities in comparison with other apple varieties, while phlorizin showed the strongest 1,1-diphenyl-2-picylhydrazyl free radical scavenging rate (73.5 ± 2.7%), oxygen radical absorbance capacity value (44.6 ± 3.1 μmol TE/g), hydroxyl radical scavenging capacity value (61.9 ± 3.5 μmol TE/g), and ferric reducing antioxidant power value (0.53 ± 0.37 μmol TE/g). The antioxidant capacities of the polyphenol extract was related not only to its total polyphenol content but also to the phenolic composition.     

Mass transfer modelling in ultrasound assisted osmotic dehydration of kiwi fruit

In this study, the effect of ultrasonic pre-treatment on osmotic dehydration of kiwi slices was investigated. Kiwi fruit slices were subjected to ultrasonic pre-treatment in a sonication water bath at a frequency of 25 kHz for 20 min. Osmotic dehydration of ultrasonic pre-treated samples were conducted for a period of 300 min in 60 Brix sucrose solution. The kinetics of moisture loss and solute gain during osmotic dehydration were predicted by fitting the experimental data with Azuara's model and Weibull's model. The effects of ultrasound application on water loss, sugar gain, effective moisture diffusivity and solute diffusivity of the samples were analysed. The osmotic dehydration process showed a rapid initial water loss followed by a progressive decrease in the rates in the later stages. From the Azuara's model, the predicted equilibrium water loss value for ultrasound pre-treated sample was 58.4% (wb) at 60°C that was nearly 16% higher than the samples treated under atmospheric conditions. Fitting of Weibull model showed that the ultrasound pre-treated and untreated samples had shape parameter (β_w) ranging between 0.570–0.616 and 0.677–0.723 respectively. The lower values of shape parameter indicated that sonication caused accelerated water loss resulting faster dehydration rate. Results indicated that the effective moisture diffusivity and solute diffusivity was enhanced in ultrasonic pre-treated samples. The effective moisture diffusivity during osmotic dehydration of ultrasonic pre-treated samples was ranged between 5.460×10⁻¹⁰–7.300×10⁻¹⁰ m²/s and solute diffusivity was varied between 2.925×10⁻¹⁰–3.511×10⁻¹⁰ m²/s within the temperature range 25–60 °C. The enhanced moisture and solute diffusivity in ultrasound pre-treated kiwi slices was due to cell disruption and formation of microscopic channels.     

The Effects of Ultrasound Treatment and Nano-zinc Oxide Coating on the Physiological Activities of Fresh-Cut Kiwifruit

This study evaluated the efficacy of ultrasound treatment and nano-zinc oxide (ZnO) coating individually and in combination in preserving the quality of fresh-cut kiwifruit. The nano-ZnO coating solution was prepared by mixing the ZnO nanoparticles in premixed chitosan–acetic acid solution. The fresh-cut kiwifruit were dipped in NaClO solution (50 μL?L^?1 sodium, control), subjected to ultrasound treatment (40 KHz, 350 W, 10 min), or coated with nano-ZnO solution. The fresh-cut kiwifruit samples were also subjected to combined ultrasound treatment and nano-ZnO coating. All of these test samples were stored at 4 °C for 10 days. The effects of these treatments on the quality parameters such as the production of carbon dioxide and ethylene, mass loss, and flesh firmness were investigated. At the end of storage, the combination treatments with ultrasound treatment at 40 KHz with 1.2 g?L^?1 nano-ZnO coating showed lower production of ethylene (1.86 μL?kg^?1?h^?1) and carbon dioxide (10.01 mg?kg^?1?h^?1), water loss (0.46 %), and texture (7.87 N). Hence, it was concluded that the combination of ultrasound treatment with nano-ZnO coating is a promising approach to extend the shelf-life of fresh-cut kiwifruit.     

The Use of Microwave and Pulsed Electric Field as a Pretreatment Step in Ultrasonic Extraction of Polyphenols from Defatted Hemp Seed Cake (Cannabis sativa) Using Response Surface Methodology

The use of microwave and pulsed electric field (PEF) processing to optimize polyphenol extraction from defatted hemp seed cake in mixed solvent of methanol, acetone and water (MAW, 7:7:6 v/v/v) was investigated using the Box-Behnken response surface method. A variables combination for microwave processing of time, microwave power and liquid to solid (L:S) ratio and for PEF (ethanol concentration, time, frequency and voltage) were used in the investigation. Following microwave or PEF treatments, the polyphenols were extracted from the samples under ultrasound with fixed variables (200 W of ultrasonic power, water bath of 70 °C and 20 min of extraction time). The measured responses were total phenolics (TP), total flavonoids (TF), DPPH˙ scavenging activity and ferric reducing/antioxidant power (FRAP). The optimum variables combination for microwave processing (5 min treatment time, L:S ratio of 6, 700 W power and volume 30 mL) and PEF-assisted extraction (voltage (30 V), frequency (30 Hz), ethanol concentration (10 %) and time (10 s)) resulted in maximum yields in all measured responses. The results suggest that microwave processing and PEF can be integrated in processing defatted hemp seed cake to enhance polyphenol extraction and maximize the yield.     

Unfreezable Water in Apple Treated by Pulsed Electric Fields: Impact of Osmotic Impregnation in Glycerol Solutions

The effects of pulsed electric fields (PEF) and osmotic impregnation in glycerol solution on the amount of unfreezable water in apple were determined by means of low-temperature differential scanning calorimetry (DSC). The obtained data were compared with behaviour of pure water–glycerol solutions (sample WG). PEF treatment was applied using a near-rectangular monopolar generator with pulse duration of 100 μs at electric field strength of 800 V/cm. The osmotic impregnation of PEF-treated apple discs was done using water–glycerol (sample AWG) and apple juice–glycerol (sample AJG) osmotic solutions at different concentration of water or juice in glycerol, W = 30–100 wt%. The data evidenced that for the PEF-treated samples the glycerol was able to penetrate successfully inside apple tissue. The state diagrams for WG, AWG and AJG samples were rather similar. It was observed that free water existed only for moisture content above some minimum value. The unfreezable water content was the largest in AJG, followed by WG and AWG. The juice concentration in glycerol W ≈ 80 wt% was found to be optimal for preservation of the texture of PEF-treated samples.     

RP-HPLC-DAD Determination of Phenolics in Industrial Apple Pomace

Processing of apple fruits for juice/cider production generates large volume of pomace at industrial scale. This biomass (cell wall material and pulp tissues) is rich in array of nutrients, especially dietary fiber and polyphenols. Apple fruits confront various processing conditions at industrial level, influencing the biochemical composition of generated pomace, including its phenolic profile. In present study, a simple, fast and reproducible reversed-phase high-performance liquid chromatography method using diode array detector was developed and validated for separation of different phenolics present in industrial apple pomace. The present method showed reliable and reproducible intraday (0.2–4.0 % RSD) and interday (3.7–8.1 % RSD) precision with limits of detection and quantification values in range of 0.14–0.58 and 0.48–1.95 μg ml^?1, respectively, for all the phenolics. Different solvent-mediated extraction of dried pomace powder was also performed to evaluate its total antioxidant potential using standard spectrophotometric assays. The major phenolics found in industrial apple pomace extracts were quercetin (1.4–10.3 μg mg^?1), phloretin (1.1–9.3 μg mg^?1) and phloridzin (0.62–2.0 μg mg^?1).     

Colonic availability of polyphenols and D-(-)-quinic acid after apple smoothie consumption

Scope : The aim of this study was to determine the amounts of polyphenols and D ‐(?)‐quinic acid reaching the ileostomy bags of probands (and thus the colon in healthy humans) after ingestion of apple smoothie, a beverage containing 60% cloudy apple juice and 40% apple puree. Methods and results : Ten healthy ileostomy subjects each ingested 0.7 L of apple smoothie (a bottle). Their ileostomy bags were collected directly before and 1, 2, 4, 6 and 8 h after smoothie consumption, and the polyphenol and D ‐(?)‐quinic acid contents of the ileostomy fluids were examined using HPLC‐DAD and HPLC‐MS/MS. The total polyphenol and D ‐(?)‐quinic acid content of the apple smoothie was determined to be 1955.6±124.6 mg/0.7 L, which is very high compared to cloudy apple juices. The most abundant substances found in the ileostomy bags were oligomeric procyanidins (705.6±197.9 mg), D ‐(?)‐quinic acid (363.4±235.5 mg) and 5‐caffeoylquinic acid (76.7±26.8 mg). Overall recovery of ingested polyphenols and D ‐(?)‐quinic acid in the ileostomy bags was 63.3±16.1%. Conclusions: The amounts of polyphenol and D ‐(?)‐quinic acids reaching the ileostomy bags are considerably higher after apple smoothie consumption than after the consumption of cloudy apple juice or cider. These results suggest that the food matrix might affect the colonic availability of polyphenols, and apple smoothies could be more effective in the prevention of chronic colon diseases than both cloudy apple juice and apple cider.     

Kinetics of Polyphenol Losses During Soaking and Drying of Cider Apples

A regular consumption of fresh or processed fruits can contribute to preventing cardiovascular diseases and cancer. Polyphenols, which are naturally present in fresh apples (Malus x domestica), are widely acknowledged as antioxidants. Cider apples contain high concentrations of polyphenols, but their composition differs markedly as a function of cultivar. Two of which were studied in this respect. The first cultivar was Marie Menard, which is highly concentrated in polyphenols and has a standard profile showing high levels of hydroxycinnamic acids and monomeric catechins, widely involved in oxidation reactions catalyzed by the polyphenol oxidase; the second one was Guillevic, which has an atypical phenolic profile for a cider apple, with highly polymerized procyanidins and no monomeric catechins, which thus induces a low sensitivity to enzymatic browning. Both cultivars were subjected to osmotic dehydration at two temperatures (45 and 60 °C) or to convective air-drying, and a combination of the two processes was also tested. Phenolic compounds were quantified by high performance liquid chromatography for various processing times and regardless of the quantity of impregnated sugar. The results revealed different behaviors depending on the polyphenolic groups of compounds. Procyanidins were better preserved by the processes than hydroxycinnamic acids or monomeric catechins. Indeed, these latter groups of polyphenols were first of all involved in enzymatic browning but could also diffuse more easily as their molecular weight was lower. Polyphenol retention was also dependent on the process applied. Polyphenols were better retained by convective drying than by osmotic dehydration, and when soaking was applied as a pretreatment, polyphenol losses were limited during subsequent drying. Moreover, the level of sucrose impregnation could mask the astringency of procyanidins.     

Phytochemical Polyphenol Extraction and Elemental Composition of Vitis labrusca L. Grape Juices Through Optimization of Pectinolytic Activity

Grape juice is a natural source of polyphenols with potential health benefits. The aim of this study was to assess the optimized basis of the pectinolytic activity through a multivariate design for the bioactive enrichment of polyphenols in grape juices and to evaluate the effect of pectinases on the extraction of minerals by ICP-MS and FAAS. Grape juices were treated with pectinases Everzym® Color and Rapidase® Smart at different conditions of enzyme concentration (0.16–1.84 g L^?1), temperature (14.8–83.6?ºC), and incubation time (9.6–110.5 min), and the effect on total phenolics, anthocyanin content, and antioxidant activity of juices were determined by employing a second-order central composite design in combination with response surface methodology. The different conditions showed significant variations in polyphenol levels of grape juices. For both of the enzymes, the increase of temperature and enzyme concentration led to a higher extraction of polyphenols, with a significant effect. Estimated effects depict a good correlation among dependent variables. For Rapidase, the optimized extraction of polyphenols was determined at an enzyme concentration of 1.57 g L^?1 and at a temperature of 54.8?ºC. For Everzym, higher concentrations of polyphenols were obtained at the enzyme concentration of 1.30 g L^?1 at 46.8?ºC. The extraction using the Rapidase enzyme significantly increased the levels of Na, K, Mg, and Fe in grape juices (p?<?0.05). The pectinolytic activity increased the polyphenol and mineral concentrations in grape juices. In addition, the optimal conditions of the pectinolytic treatment comprise a feasible alternative to improve the bioactive potential of grape juices.     

Inactivation of Escherichia coli with Power Ultrasound in Apple Cider

The use of acoustic energy to secure apple cider safety was explored. Inactivation tests were performed with Escherichia coli K12 at 40 °C, 45 °C, 50 °C, 55 °C, and 60 °C with and without ultrasound, followed by a validation test with E. coli O157:H7 at 60 °C. The cell morphology was observed with environmental scanning electron microscopy for samples treated at 40 °C and 60 °C. Physical quality attributes of the apple cider (pH, titratable acidity, °Brix, turbidity, and color) were compared for treated samples. The inactivation tests showed that sonication increased E. coli K12 cell destruction by 5.3‐log, 5.0‐log, and 0.1‐log cycles at 40 °C, 50 °C, and 60 °C, respectively. The additional destruction due to sonication was more pronounced at sublethal temperatures. At the lethal temperature of 60 °C, the rate of death by ultrasound was not significantly different compared with the thermal‐alone treatment. The inactivation of E. coli K12 with heat was described by 1st‐order kinetics, especially at 50 °C and 60 °C. For ultrasound treatments, concave upward survival curves were observed, which had a shape factor in the range of 0.547 to 0.720 for a Weibull distribution model. Extensive damage for ultrasound treated E. coli K12 cells, including cell perforation, was observed. Perforation is a unique phenomenon found on ultrasound‐treated cells that could be caused by liquid jets generated by cavitation. Titratable acidity, pH, and °Brix of the cider were not affected by ultrasound treatment. Minor changes in color and turbidity for ultrasound treated samples, especially for sonication at 40 °C for 17.7 min, were observed.     

Juices, Fibres and Skin Waste Extracts from White, Pink or Red-Fleshed Apple Genotypes as Potential Food Ingredients

This study measures and compares the bioactive content and appearance attributes of juices, dietary fibres (DFs) and skin wastes of three apple genotypes (white fleshed (WF), pink fleshed (PF) and red fleshed (RF)). The juices of the PF and RF apples had more appealing and stable colours and much greater total extractable polyphenol content (TEPC) (RF had the highest, 3.40 mg catechin equivalent/mL juice) and vitamin C (PF had the highest, 14.2 mg/100 mL juice), compared with the WF apple. DFs isolated from the three apples using aqueous and ethanolic methods varied in bioactive profiles as a function of genotype. The TEPC and antioxidant activity (AA) of the fibres decreased in the order of PF > RF > WF. The total DF (TDF) in the fibre obtained using the aqueous method decreased in the order of RF?>?PF?>?WF. The ethanolic method yielded higher neutral monosaccharide (NM) and slightly greater TDF contents than the aqueous method. More polyphenol species were detected in the PF fibres, especially those obtained using the aqueous method. The polyphenol content in the apple skin decreased in the order of RF > WF > PF, with PF having slightly more pectic polysaccharides. As a whole, the RF apple appeared to be the best genotype as the potential source for juice, fibre and skin waste extract (SWE) ingredients. The PF apple would be the second best genotype for juice and fibre ingredients. The skin of the RF and WF genotypes would provide a good source of polyphenols. There is potential for promoting RF and PF apple genotypes because of their excellent nutritional values. The aqueous fibre preparation method used herein containing no solvent treatment and freezing steps represents an industrial-scale cost-effective alternative to the conventional ethanolic methods used for producing DFs whilst retaining polyphenols.