Apple Puree Research Articles

Effect of Storage Conditions on the Stability of Polyphenols of Apple and Strawberry Purees Produced at Industrial Scale by Different Processing Techniques.

During a food product's life, storage conditions affect its composition of nutrients, bioactive compounds, and sensory attributes. In this research, strawberry and apple purees were selected as a model to examine how the storage of various purees industrially produced with different technologies affect the bioactive phenolic compounds, color, and sensory attributes. Specifically, fruit products processed on an industrial scale by different technologies including freezing, thermal treatment (mild and standard), and high-pressure processing were studied, as well as storage for up to 12 months at -20, 4, and 24 °C. In strawberry puree, storage conditions had a stronger impact on phenolic compound levels, particularly on anthocyanins, whereas in apple puree, the initial processing techniques exerted a greater influence than storage conditions, mainly caused by the hot or cold crushing processes. In general, proanthocyanidins were the major phenolic group and the most stable during storage, while anthocyanins were the group most affected by both processing and storage. Apple flavonols and dihydrochalcones were quite stable, while strawberry ellagitannins suffered higher degradations during storage. Through our analysis, it is found that during storage, the stability of polyphenols in each fruit is different, and processing and storage can be either detrimental or even beneficial. The selection of the ideal storage conditions (time and temperature) is a key factor to maintaining the polyphenol content in sensitive fruits such as strawberries. However, storage conditions are in some cases more important to minimizing the polyphenol losses than how the product is processed.

Prospects for the use of sweeteners in the production of pastille confectionery

Data on the current health condition of the population convincingly proves the need to reduce the caloric content of the diet, reducing the amount of added sugar and animal fats in products. However, people cannot give up confectionery and sweet dishes, which have a positive effect on the feeling of completion of a meal and mood. Therefore, the purpose of this paper is to develop a recipe and marshmallow technology with a full replacement of sugar for erythritol. Moreover, the author partially replaced the traditional mashed apple with black currant puree in the marshmallow recipe to improve organoleptic characteristics and increase the content of essential nutrients. The author also studied the effect of erythritol and black currant puree on the marshmallow mass and finished products quality parameters. The author carried out the research using commonly accepted methods. The author experimentally proved a positive effect of replacing apple puree with 40% black currant puree on the quality indicators of semi-finished and finished products. The author substantiated the possibility of replacing sugar with erythritol and investigated the addition of the FitParad No. 10 sweetener mixture to enhance the sweetness of the finished product. Considering the results of the research, the author has developed a recipe and technology for sugar- free white marshmallows. It is proved that marshmallow based on erythritol as a sugar substitute is not available according to literature data and market analysis of pastry confectionery products.

Разработка и применение балльной шкалы для органолептической оценки качества фруктовых снеков

The article presents the results of the scoring scale development, obtained using a descriptive method of organoleptic analysis, to assess the fruit snacks quality and the process of their production. The individual quality indicators nomenclature, the weighting coefficients (for appearance – 0,6; surface texture – 0,2; structural texture – 0,2; separability of the product – 1,0), the value boundary limits of integrated and individual indicators for each quality category score (great – 4,5–5,0; good – 4,4–3,7; satisfactory – 3,6–2,5; barely satisfactory – 2,4–1,8; unsatisfactory (unacceptable) – less than 1,7) were defined. The scoring scale was tested for organoleptic assessment of the quality of dehydrated apple puree with different content of soluble solids (84–96% d.b.) and water activity value (0,38–0,76). Тhe scoring scale applicability to identify the product organoleptic and technological advantages and disadvantages and select the process parameters for structuring of snacks is reported.

Effect of sterilization conditions on the formation of furan and its derivatives in canned foods with different substrates.

This study explored the effects of sterilization conditions on the formation of furan and its 10 derivatives in canned foods with a sterilizing value (F0) at 4. The contents of furans were determined by SPME arrow-GC-MS/MS, along with the furan precursors analyzed for elucidating the possible mechanism of furan formation. Results revealed that the total furan contents rose substantially in canned meat paste, tomato mackerel, chicken puree, tomato paste, pineapple slice, pineapple juice and carrot juice following sterilization. However, the total furan content did not change significantly ( p > 0.05) in canned oily mackerel, but decreased significantly ( p < 0.05) in canned apple puree after sterilization. With the exception of apple puree and pineapple slice, all the other canned foods showed a higher total furan content under low-temperature-long-time condition than that under high-temperature-short-time condition. Following heating, only the furan level showed a large increase in chicken puree, meat paste and tomato mackerel, whereas in canned fruit- and vegetable-based foods, the contents of furan and furfural showed a pronounced increase. The levels of alkylated furans were higher in sterilized samples containing high level of amino acid, while that of oxygenated furans were higher in sterilized samples containing high level of reducing sugar.

A novel soft robotic pediatric in vitro swallowing device to gain insights into the swallowability of mini-tablets

Soft robotics could help providing a better understanding of the mechanisms underpinning the swallowability of solid oral dosage forms (SODF), especially by vulnerable populations such as the elderly or children.In this study a novel soft robotic in vitro device is presented, the Pediatric Soft Robotic Tongue (PSRT), inspired by the literature data on the anatomy and physiology of a 2-year-old child. Multi-particulate oral formulations (i.e., mini-tablets (MT)) were considered, including different scenarios such as SODF carrier (i.e., soft-food, liquid), administration methods, SODF size and volume fraction.In vitro results showed that semi-solid foods like yoghurt and apple puree (shear viscosity above ∼ 150 mPa.s at γ̇ = 50 s−1, and its yield stress up to ∼ 5 Pa) may be considered more suitable than thin liquids (i.e., xanthan gum 0.25 %) for swallowing MT. However, the reduction of MT size did not bring any benefit in terms of swallowability in the range studied. Regarding the administration method, spreading MT on top of a teaspoon full of carrier should be preferred over mixing MT with the carrier or placing MT on the tongue first to favour their swallowability. Finally, and under the in vitro conditions studied using yoghurt as carrier, it would be possible to increase the volume fraction of SODF up to 0.20 without influencing swallowability according to the three parameters evaluated (% of MT swallowed, bolus velocity, and post-swallow residues). These results should help to design more focused sensory and/or clinical tests to improve product formulation and patient acceptability.

Untargeted Metabolomics Reveals New Markers of Food Processing for Strawberry and Apple Purees.

In general, food processing and its conditions affect nutrients, bioactive compounds, and sensory characteristics of food products. This research aims to use a non-targeted metabolomics approach based on UPLC-ESI-QTOF-MS to determine how fruit processing can affect the metabolic profile of fruits and, through a comprehensive metabolic analysis, identify possible markers to assess their degree of processing. The present study uses a real case from the food industry to evaluate markers of the processing of strawberry and apple purees industrially elaborated with different processing techniques and conditions. The results from the multivariate analysis revealed that samples were grouped according to the type of processing, evidencing changes in their metabolic profiles and an apparent temperature-dependent effect. These metabolic profiles showed changes according to the relevance of thermal conditions but also according to the exclusively cold treatment, in the case of strawberry puree, and the pressure treatment, in the case of apple puree. After data analysis, seven metabolites were identified and proposed as processing markers: pyroglutamic acid, pteroyl-D-glutamic acid, 2-hydroxy-5-methoxy benzoic acid, and 2-hydroxybenzoic acid β-d-glucoside in strawberry and di-hydroxycinnamic acid glucuronide, caffeic acid and lysoPE(18:3(9Z,12Z,15Z)/0:0) in apple purees. The use of these markers may potentially help to objectively measure the degree of food processing and help to clarify the controversial narrative on ultra-processed foods.

EFFECT OF FORMULATION VARIABLES ON SENSORY QUALITY OF THERMO-REVERSIBLE FRUIT FILLING FOR FROZEN SEMI-FINISHED BAKERY PRODUCTS: MODELLING AND OPTIMIZATION

Development of a food product requires integrated scientific and professional knowledge on the technological process, the final product and, the quality of the ingredients and their interaction. This research examined the effect of formulation variables on the sensory quality of a thermo-reversible sour cherry fruit filling, as well as the modelling and optimization of the variables for achieving the quality suitable for filling frozen semi-finished bakery products in industrial conditions. Each formulation for 15 model-samples was successively corrected, to achieve the appropriate sensory quality of the filling in finished products after baking. Their quality was evaluated by descriptive sensory and physico-chemical methods of analysis and compared. The basic formulation for the filling was defined after the successive production of 7 model-samples in laboratory conditions, their use in industrial conditions (puff pastry filling, shaping, quick freezing, storage for at least 24 hours at -18°C, baking and cooling to room temperature) and analysing their quality. Further formulation optimization included selecting: the type and amount of fruits (sour cherry, apple), food additives and cherry flavour for 8 new model-samples. The formulation and ingredients for the fruit filling production (30% sour cherry fruit, 30% apple puree, 58% sugar, 2% starch, 1% pectin, 0.03% firming agent E509, 0.03% acidity regulator E331, 0.025% cherry flavour) and quality parameters (dry matter 65%, acidity 0.85%, pH = 3.2-3.4) were defined. The fruit filling had appropriate sensory quality before and after baking of filled puff pastry: clear cherry-red colour, moderately firm consistency and stable volume, rich fruity aroma, and refreshing sweet-sour taste. The results also confirmed that the product was suitable for manual or machine filling of raw dough.

The Flavonoid Molecule Procyanidin Reduces Phase Separation in Model Membranes.

Procyanidin extracted from fruits, such as apples, has been shown to improve lipid metabolization. Recently, studies have revealed that procyanidin interacts with lipid molecules in membranes to enhance lipid metabolism; however, direct evidence of the interaction between procyanidin and lipid membranes has not been demonstrated. In this study, the phase behaviors and changes in the membrane fluidity of cell-sized liposomes containing apple procyanidin, procyanidin B2 (PB2), were demonstrated for the first time. Phase separation in 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/cholesterol ternary membranes significantly decreased after the addition of PB2. The prospect of applying procyanidin content measurements, using the results of this study, to commercial apple juice was also assessed. Specifically, the PB2 concentrations were 50%, 33%, and 0% for pure apple juice, 2-fold diluted apple juice, and pure water, respectively. The results of the actual juice were correlated with PB2 concentrations and phase-separated liposomes ratios, as well as with the results of experiments involving pure chemicals. In conclusion, the mechanism through which procyanidin improves lipid metabolism through the regulation of membrane fluidity was established.

Apple Puree as a Natural Fructose Source Provides an Effective Alternative to Artificial Fructose Sources for Fuelling Endurance Cycling Performance in Males

Carbohydrate consumption during exercise enhances endurance performance. A food-focused approach may offer an alternative, ‘healthier’ approach given the potential health concerns associated with artificial fructose sources, but food-based carbohydrate sources may increase gastrointestinal (GI) symptoms. This study compared the cycling performance and GI comfort of two different fructose sources (fruit and artificial) ingested during exercise. Nine trained male cyclists (age 24 ± 7 years; VO2peak 65 ± 6 mL/kg/min) completed a familiarisation and two experimental trials (60 g/h carbohydrate, 120 min at 55% Wmax and ~15 min time trial). In the two experimental trials, carbohydrate was ingested in a 2:1 glucose-to-fructose ratio, with fructose provided as artificial crystalline fructose (GLU/FRU) or natural apple puree (APPLE PUREE) and maltodextrin added to provide sufficient glucose. Time trial (TT) performance was not different between trials (GLU/FRU 792 ± 68 s, APPLE PUREE 800 ± 65 s; p = 0.313). No GI symptoms were significantly different between trials (p ≥ 0.085). Heart rate, blood glucose/lactate concentrations, and RPE were not different between trials, but all, excluding blood glucose concentration, increased from rest to exercise and further increased post-TT. Apple puree as a natural fructose source provides an alternative to artificial fructose sources without influencing cycling performance or GI symptoms.

Effects of Nutrients and Growth Regulators on Seed Germination and Development of Juvenile Rhizome Proliferation of Gastrodia elata In Vitro

Two prevalent issues with Gastrodia elata growing in a natural wild environment are the necessary symbiotic seed germination with Mycena spp. and the long growing cycle of protocorms into mature rhizomes with Armillaria mellea. This study explored the most suitable nutrients to germinate seeds and the developmental stages and propagated protocorm/juvenile rhizomes (jrhs) through a tissue culture approach. Adding humic acid, mashed potato, peptone, and (indole-3-acetic acid) IAA to the 2 g/L Hyponex 7-6-19 basal medium accelerated seed germination into protocorms with an average length of 2 mm. The nutrients best for the in vitro propagation of jrhs consisted of 1 g/L Hyponex 7-6-19 and MS salts with 1/2 NH4NO3 and KNO3, 2 mg/L BA, 2 mg/L NAA, 2 g/L tryptone, 2 g/L glutamic acid, 1 g/L chitosan, 10 g/L apple puree, 20 g/L mashed potato, 100 mL/L coconut water, and 1.5 g/L A. mellea powder, at a pH level of 6. The maximum length and number of jrhs were 17.2 ± 0.8 mm and 76.6, respectively, in two subcultures. The in vitro propagation system started from seeds of G. elata can be employed as a potential method to propagate protocorm/jrhs for the cultivation of mature rhizomes from indoor or outdoor cultures.

DETERMINATION OF PATULIN IN APPLE PUREE USING LC-MS WITH TRIPLE QUADRUPOLE DETECTOR

Patulin is a high-hazardous mycotoxin formed in apples affected by the fungus. This mycotoxin, when ingested, has the irreversible effect of deteriorating health. Most often, patulin enters the human body through processed apple products or baby food. The countries of the European Union have decided to reduce the level of the maximum residue level of patulin in apples to the lowest that can be measured by analytical instruments. Therefore, the aim of this work is to develop a rapid and sensitive method of patulin determination for the lowest level detection allowed by European law. In this work, patulin was artificially added to apple puree at the level of 10 μg/kg for further detection. The analysis was performed on an LC-MS/MS system with electrospray ionization type and a column based on modified silica. The mobile phase used in the analysis was ultrapure water and acetonitrile with the addition of formic acid. Measurement of the quantity of PAT in the sample was performed using MRM transitions. Subsequently, there was a problem of significant inclusion of the matrix on the spectrum, but the problem was solved by using cartridges for cleaning of matrix impurities. As a result, we achieved a successful and accurate result at level of 10 μg/kg. A calibration curve was felicitously constructed for five different concentrations. The most important parameters of validation of the method use were determined – reproducibility, repeatability, recovery and linearity. The final result of this work is the development and implementation of a rapid, cost-effective and suitable method for determining patulin at the level of the maximum residue level.

Comparison of near-infrared, mid-infrared, Raman spectroscopy and near-infrared hyperspectral imaging to determine chemical, structural and rheological properties of apple purees

Near-infrared (NIR), mid-infrared (MIR), Raman spectroscopy and hyperspectral imaging (HSI) were comprehensively compared for their capacity to evaluate the composition and texture characteristics of apple purees issued from a large variability (cultivar, fruit thinning, post-harvest mealy texture and processing). NIR, MIR and HSI techniques had a good ability to estimate puree composition such as soluble solids (RPD >2.5), titratable acidity (RPD >2.4) and dry matter (RPD >2.3). Raman spectroscopy was less accurate to determine puree biochemical (RPD <1.8) and textural parameters (RPD <1.4) than the other techniques. MIR was the best tool to identify aforementioned factors (>91.7% of correct classification) and satisfactory predict the puree average particle size (RPD = 2.9), viscosity (RPD ≥2.1) and viscoelasticity (RPD >2.3). Consequently, NIR, MIR and HSI should be prioritized as process analytical technologies to detect apple puree variability, and assess their texture and taste. • MIR provided a better discrimination of puree variability than other techniques. • MIR gave the best prediction of puree textural and rheological properties. • HSI technique had a better ability to assess puree quality and variability than NIR. • Raman spectroscopy could not provide sufficient assessment of puree quality.

Research method of rapid determination of chiral pesticide fenpropathrin enantiomers in fruit and vegetable puree by supercritical fluid chromatography.

A method is first established for the separation and determination of fenpropathrin enantiomer residues in apple puree, strawberry puree, and tomato puree considered a supplementary food for infants by supercritical fluid chromatography. After the sample was extracted with acetonitrile and cleaned up by a solid-phase extraction column, then it was separated by a CHIRALPAK AD-3 chiral column with gradient elution at a flow rate of 1.5mL/min using methanol and supercritical carbon dioxide as the mobile phase, detected by ultraviolet detector at 230nm wavelength and quantified with the external standard method. The limits of quantification of the two fenpropathrin enantiomers were both 0.2mg/kg, the linear ranges were 1.0-20.0mg/L with linear correlation coefficients greater than 0.9992, the recoveries in the spiked samples at 0.2, 0.4 and 2.0mg/kg were from 80.6 to 105%, and the relative standard deviation reached 2.6-7.7%. This method has the advantages of convenient operation, good resolution, and environmental protection, which can satisfy the requirement of determination for fenpropathrin enantiomer residues in fruit and vegetable puree as supplementary food for infants.

RESEARCH OF THE PROCESS OF LOW TEMPERATURE CONCENTRATION OF FOOD RAW MATERIALS FOR ZEFIR MANUFACTURE

The article investigated the recipe composition and method of low-temperature concentration of fruit and vegetable puree with the content of components: 20% apple, 20% pumpkin, 15% beet, 15% cranberry, 15% hawthorn. Concentration of puree is carried out in a rotary evaporator to a dry matter content of 50% at a temperature of 50… 56 ° C under vacuum. At the same time, the processing time was reduced by 1… 2 min, which is many times less compared to traditional single-hull vacuum evaporators (60… 90 min). Reducing the temperature effect of concentration helps to increase the organoleptic and physicochemical parameters of the resulting paste. To establish the effect of the contribution of each component on the structure of the paste, the structural and mechanical properties of the puree of each raw material and concentrated semi-finished products were studied. The developed paste has increased strength of the structure with a value of dynamic viscosity - 394 Pa ∙ s, which is 2.5 times more than the control sample. The developed blended fruit and vegetable paste has an increased content of physiological and functional ingredients and the best organoleptic characteristics in contrast to the control version (apple paste). It is established that partial replacement of apple puree (up to 75%) in the prescription composition of marshmallows with the developed multi-component fruit and vegetable paste gives the product original properties. An increase in the value of the dynamic viscosity of marshmallows with a content of 75% replacement of apple puree with the developed paste compared to the control sample (marshmallows without additives) from 408 Pa ∙ s to 908 Pa ∙ s. The color of the marshmallow mass with 75% replacement of apple puree is bright pink with a wavelength of 596.7 nm and a brightness of 62.3%. The obtained data allow to improve the quality of original marshmallows by adding fruit and vegetable semi-finished products with increased functional properties.

The True Amino Acid Digestibility of 15N-Labelled Sunflower Biscuits Determined with Ileal Balance and Dual Isotope Methods in Healthy Humans

BackgroundSunflower is a promising protein source but data on amino acid (AA) digestibility are lacking in humans. Classically, the determination of AA digestibility requires ileal digesta sampling. The dual isotope method is minimally invasive but has not been compared to the conventional approach. ObjectivesThis study aimed to determine the true ileal digestibility of sunflower AAs in healthy volunteers who ate biscuits containing 15nitrogen (N) protein isolate, in comparison with the dual isotope method. MethodsTwelve healthy volunteers (men and women; 40.4 ± 10.5 years old; BMI, 23.7 ± 2.9 kg/m2) were equipped with a naso-ileal tube. For 4 hours, they consumed 9 repeated meals comprising 15N-sunflower protein biscuits together with 13carbon (C)-AAs, carried either in chocolate (SUN + Ch; n= 7) or apple puree (SUN + P; n= 5). Ileal digesta and blood were sampled throughout 8 hours after ingestion of the first meal. The 15N and 13C AA enrichments were measured in digesta to determine ileal digestibility directly and in plasma to determine lysine and threonine digestibility using the dual isotope method. Differences between methods and between vector groups were analyzed using paired and unpaired t-tests, respectively. ResultsThe ileal digestibility of sunflower indispensable AAs (IAA) was 89% ± 5.3%, with threonine and lysine having the lowest digestibility. In the SUN + Ch meal, IAA digestibility was 3% below that of SUN + P (P < 0.05). The mean free 13C-AA ileal digestibility was 98.1% ± 0.9%. No matter which matrix was used to carry 13C-AAs, plasma 15N and 13C-AA kinetics displayed a 1-hour offset. Digestibility obtained with the dual isotope method (70.4% ± 6.0% for threonine and 75.9% ± 22.3% for lysine) was below the target values. ConclusionsThe ileal digestibility of IAAs from a sunflower isolate incorporated in a biscuit was close to 90% in healthy adults. Under our experimental conditions, the dual isotope method provided lower values than the usual method. Further protocol developments are needed to validate the equivalence between both methods. This trial was registered at http://www.clinicaltrials.gov clinicaltrials.gov as NCT04024605.

Addition effect of Phoenix canariensis date and different food by-products on the physicochemical and sensory properties of jelly candy

Jelly candy is an appreciated food for consumers, especially children. Its fortification with functional ingredients could show an interesting effect on human health. This study aimed to define the structural and chemical characteristics, especially that of polyphenolic amounts, of apple candies prepared with different percentages (2, 4, and 6%) of grape by-products (Moscato, Chardonnay, Barbera, and Pinot noir), cocoa bean shell (CBS), coffee silverskin and canary date powder, and to evaluate the consumer overall acceptance of these products. The fortification was achieved by replacing different percentages of apple puree with by-product powders. The jelly candies with the canary date and Pinot noir by-product showed the highest quantities of polyphenolic compounds (6.18 and 4.54mg GAE/g DW, respectively) and the greatest antioxidant capacity (24.04 and 26.54µmol TE/g DW, respectively) while the coffee silverskin candy had the lowest values. In general, the use of canary dates and by-product powders in candy production increased hardness, polyphenol and fiber contents, and antioxidant capacity. Sensory analysis showed that the candies obtained with coffee silverskin powder had the least overall liking at 6% substitution. However, no significant differences were recorded between the control and candies at 2 and 4% substitution for all studied functional ingredients

BLUEBERRY, SEA BUCKTHORN FRUITS AND APPLE BEVERAGE: BIOCHEMICAL AND SENSORIAL CHARACTERIZATION

This work aimed at optimizing the extraction of total phenolic (TP) and total monomeric anthocyanin (TMA) content for the development of a potentially functional wild blueberry smoothie (BP) with apple puree (AP), apple juice (AJ) and sea buckthorn puree (SBJ) in various proportions using conventional extraction (CE) and advanced extraction techniques [ultrasound-assisted (UAE)]. There were also analyzed the rheological behavior and the color attributes (lightness and redness respectively) of smoothie samples. S7 smoothie sample [30 AP/30 AJ/20 SBJ/20 BP (UAE)] provided a beverage with significant higher amount (21.40%) of anthocyanins (TMA) compared to sample S10 [30 AP/30 AJ/20 SBJ/20 BP (CE)] in which the extraction of anthocyanins was by the classical method. Further, different color attributes, particularly brightness (L *), redness (a *) and yellow (b *) decreased considerably for the samples with 15 and 20% addition of blueberry puree. Therefore, ultrasound-assisted extraction had a significant effect on the amount of anthocyanins extracted, compared to the classical extraction method.

Dependence of surface tension of fruit puree on temperature exposure

When developing food products with new properties using innovative technologies, it is important to obtain data on the physicochemical, thermal-physical and structural-mechanical properties of the processed food media. So, one of the key components in the selection of the mode of collapsing ultrasonic cavitation is the surface tension of vegetable purees. The paper presents research data (2020) on the effect of temperature on the surface tension coefficient of fruit puree of different viscosity. The objects of research are cherry plum, pear and apple puree, combined in a row by viscosity. The surface tension coefficient was determined by the stalagmometric method, for which the puree was preliminarily centrifuged. The measurements were carried out at temperatures of 25 and 35 °С. It was found that, under equal conditions of centrifugation of puree, the proportion of supernatant in pear puree is noticeably higher – 77.37 % to the weight of puree in comparison with cherry plum puree (67.20 %) and apple puree (52.75 %). This fact can be explained by the presence of stony cells in the former which form an incompressible sediment, which allows a greater separation of the dispersed phase (sediment) and the dispersion medium (supernatant). It was found that the coefficient of surface tension of fruit purees, despite the slight difference, decreases with increasing temperature. Analysis of the steepness of the slope of the curve characterizing the effect of temperature on the surface tension coefficient showed that temperature stabilization during technological processing is more required for pear puree.

Application of Different Compositions of Apple Puree Gels and Drying Methods to Fabricate Snacks of Modified Structure, Storage Stability and Hygroscopicity

The aim of this study was to determine the effect of incorporation of apple puree and maltodextrin to agar sol on the sorption properties and structure of the dried gel. The effect of different drying methods on the sorption behaviour of aerated apple puree gels was also observed. The gels with the addition of 25% and 40% concentration of apple puree and with or without maltodextrin were prepared and dried. The foamed agar gel was subjected to freeze-drying, air-drying and vacuum-drying. The sorption properties of dried gels (adsorption isotherms, water uptake in time) were investigated. The relations between the glass transition temperature, water activity and water content were also obtained for some apple snacks. The increase in apple puree in freeze-dried gels increased the hygroscopicity and decreased the glass transition temperature (Tg). The water content at given activity and hygroscopicity were reduced by the addition of maltodextrin, which also caused the increase in Tg. The application of different drying methods enabled obtaining different structures of material. The open-pore, fragile materials were obtained by freeze-drying, the expanded matrix with big holes was characteristic for vacuum-dried gels, but the closed pores with thick walls were created during the air-drying.

TiO2 nanoparticles reagent based nonenzymatic label-free optical sensor for the rapid detection of L-lactate in apple juice

L-lactate is an essential organic chemical in food processing, clinical, chemical, and fermentation industries. Titanium oxide nanoparticles (TiO2 NPs) was synthesized by the green chemical method and structural, morphological, zeta potential characterization studies were performed for achieving lower limit of detection (LOD), stability, and sensor fabrication. First time reporting TiO2 NPs functionalized with 3-aminophenylboronic acid (3-APBA^TiO2 NPs) for L-lactate detection in apple puree (lab prepared) and commercial Tropicana (Indian local brand) apple juice samples. Nanocomposite in the aqueous phase (pH 7.4) shows a selective binding towards L-lactate that results in a blue shift of UV-VIS absorption wavelength from 300 nm to 288 nm as L-lactate binds to the boron atom of boronic acid and forms a tetragonal complex stabilized by the TiO2 NPs. The apple samples spiked with L-Lactate (1-10 mM) showed an absorption peak intensity increases as per lactate concentration with the LOD= 3.11 mM using the calibration graphs. The nanosensor data was validated with a commercial Megazyme kit and conventional High-performance liquid chromatography (HPLC) technique. L-lactate content in commercial Tropicana apple juice samples was detected as 6.1 mM with 93.5 % correlation. This method could be an alternative to conventional L-lactate detection techniques and can be interfaced with a smartphone for onsite detection device development.