ALULOSA COMO ENDULZANTE ALTERNATIVO PARA REDUCIR EL ÍNDICE GLUCÉMICO Y LAS CALORÍAS DE LOS ALIMENTOS: ASPECTOS BIOLÓGICOS, LEGALES Y TECNOLÓGICOS / ALLULOSE AS AN ALTERNATIVE SWEETENER TO REDUCE THE GLYCEMIC INDEX AND CALORIES OF FOODS: BIOLOGICAL, LEGAL AND TECHNOLOGICAL ASPECTS

La obesidad y la prevalencia de la diabetes han aumentado progresivamente en los últimos decenios, lo cual ha conllevado a diversas recomendaciones de la Organización Mundial de la Salud (OMS) para mejorar la dieta e incorporar hábitos saludables. Con el objetivo de limitar los azúcares agregados, reducir las calorías y modular la respuesta glucémica, la industria ha implementado distintas alternativas, entre las cuales ciertos azúcares raros presentan un gran potencial. La alulosa, como sustituto de azúcares tradicionales y edulcorantes, confiere características sensoriales similares a las de los productos con sacarosa y proporciona los beneficios nutricionales esperados. El objetivo de este trabajo fue revisar los conocimientos, hasta la fecha, sobre aspectos biológicos, legales y tecnológicos de la alulosa

The obesity and prevalence of type 2 diabetes have progressively increased in the recent decades, which has led to various recommendations from the World Health Organization (WHO) to improve diet and healthy habits. With the objective of limiting added sugars, reducing calories, and modulating the glycemic response, the industry has implemented different alternatives, among which certain rare sugars have great potential. Allulose as a substitute for traditional sugars and sweeteners confers sensory characteristics like those of products with sucrose and provides the expected nutritional benefits. The aim of this work was to look over the knowledge, to date, on biological, legal, and technological aspects of allulose

Determination of Dicofol in Tea Using Surface-Enhanced Raman Spectroscopy Coupled Chemometrics.

Dicofol is a highly toxic residual pesticide in tea, which seriously endangers human health. A method for detecting dicofol in tea by combining stoichiometry with surface-enhanced Raman spectroscopy (SERS) technology was proposed in this study. AuNPs were prepared, and silver shells were grown on the surface of AuNPs to obtain core-shell Au@AgNPs. Then, the core-shell Au@AgNPs were attached to the surface of a PDMS membrane by physical deposition to obtain a Au@AgNPs/PDMS substrate. The limit of detection (LOD) of this substrate for 4-ATP is as low as 0.28 × 10-11 mol/L, and the LOD of dicofol in tea is 0.32 ng/kg, showing high sensitivity. By comparing the modeling effects of preprocessing and variable selection algorithms, it is concluded that the modeling effect of Savitzky-Golay combined with competitive adaptive reweighted sampling-partial least squares regression is the best (Rp = 0.9964, RPD = 10.6145). SERS technology combined with stoichiometry is expected to rapidly detect dicofol in tea without labels.

Citrus flavonoids against Fusarium verticillioides in post-harvest maize: Minimization of fumonisins and alteration of fungal ultrastructure.

AIMS: To minimize fumonisins (FBs) accumulation by Fusarium verticillioides in post-harvest maize, using flavonoids obtained from citrus residues: naringin (NAR), neohesperidin (NEO), quercetin (QUER), and its mixtures. METHODS AND RESULTS: Response surface methodology with Box-Behnken design was applied in maize at 0.98 and 0.95 aw . The optimal mixture found, composed of 0.40 mmol kg-1  NAR, 0.16 mmol kg-1  NEO and 0.37 mmol kg-1 QUER, reduced the accumulation of FBs B1, B2, and B3 by 88 ± 6%, 90 ± 6% and 85 ± 5%, respectively, when applied to maize at 0.98 aw . The mentioned mixture led to a 54 ± 9% reduction of fumonisin B1 accumulation in maize adjusted to 0.95 aw . These flavonoids applied individually and as a mixture, affected the structure of both the cell wall and the cytoplasm of F. verticillioides. The cell wall lost rigidity and the cells appeared highly deformed, with ruptured plasmalemma and disrupted endomembranes. CONCLUSIONS: It was possible to diminish the accumulation of FBs in maize by a highly toxigenic Fusarium strain, producing severe damage to its ultrastructure. SIGNIFICANCE AND IMPACT OF STUDY: The results indicate the possible use of flavonoids from citrus industry residues as natural and environmentally friendly antifungal agents to restrain the accumulation of FBs in stored maize.

Study of UV-C treatments on postharvest life of blueberries 'O'Neal' and correlation between structure and quality parameters.

The effect of different doses of UV-C light (5.3, 8.3 and 11.4 kJ/m2) on native mycobiota and Botrytis cinerea incidence, micro and ultrastructure, biomechanical properties and weight loss of blueberry fruit cv. O'Neal during 20 days of storage at 8 ± 1 °C was evaluated. Decay incidence was significantly reduced by all UV-C light doses for both, native mycobiota and inoculated B. cinerea. The highest UV-C dose studied (11.4 kJ/m2) was the most effective indelaying the onset of fungal and B. cinerea infection (6 and 4 days, respectively). UV-C irradiation caused some distinctive changes in fruit structure characterized by redistribution, alteration and partial removal of epicuticular waxes, reinforcement of epicarp cell walls, and modifications in the cuticle. Biomechanical parameters were not affected by UV-C treatments excepting at day 15 where irradiated samples showed higher values of rupture force (FR) and deformation (D). Structure changes partially explained the significant increase in weight loss, FR and D values in irradiated fruit after 15 days of storage. UV-C irradiation could be an alternative for delaying and reducing fungal infection. However, postharvest shelf-life of irradiated blueberries could be limited by the negative effect on weight loss.

Ozone washing decreases strawberry susceptibility to Botrytis cinerea while maintaining antioxidant, optical and sensory quality.

This work aimed to evaluate the effect of ozone washing (maximum concentration 3.5 mgL-1- 5 and 15 min) on Botrytis cinerea decay, physicochemical parameters, bioactive compounds, in vitro and in vivo antioxidant activity, and sensory properties of strawberries cv. Albion throughout refrigerated storage at 5 ± 1 °C. A 5 min long ozonation delayed the onset of B. cinerea infection by 4 days, and significantly reduced its incidence as storage progressed (~17 % lesser than in control at day 8), without impairing physicochemical parameters or sensory quality. This treatment did not affect the antioxidant activity of strawberry extracts neither in in vitro (ORAC and ABTS assays) or in vivo assays using Caenorhabditis elegans as a model organism. Higher ozone doses did not achieve greater reduction of B. cinerea decay throughout the storage period. This study demonstrated that exposing strawberries to a 5 min long aqueous ozone treatment could extend their storability at 5 °C.

Evaluation of citrus flavonoids against Aspergillus parasiticus in maize: Aflatoxins reduction and ultrastructure alterations.

In this study, the effects of citrus flavonoids naringin (NAR), neohesperidin (NEO) and quercetin (QUER) on aflatoxins accumulation by a selected Aspergillus parasiticus strain in maize at 0.95 aw were studied by response surface methodology using a Box-Behnken design. Multiple response optimization was applied to simultaneously minimize the contamination with aflatoxins (AFs) B1, G1, B2 and G2. The application of the optimal mixture in maize at 0.95 aw (0.39 mM NAR, 0.24 mM NEO and 0.40 mM QUER) reduced from 85% to 100% AFs accumulation. The same mixture at 0.98 aw, led to a reduction in AFs accumulation that ranged from 93% to 98%. Ultrastructure alterations of cellular membranes and walls in A. parasiticus, evidenced by transmission electron microscopy images, were severe and depended on the type of flavonoid and their combination. Flavonoid mixtures may provide an environmentally friendly alternative for decreasing AFs accumulation in stored maize, replacing synthetic compounds.

Botrytis cinerea response to pulsed light: Cultivability, physiological state, ultrastructure and growth ability on strawberry fruit.

Botrytis cinerea causes postharvest spoilage in important crops such as strawberry and other berries. Pulsed light (PL) treatment could be an environmentally friendly postharvest alternative to synthetic fungicides in berries. Cultivability, physiological state, ultrastructure of Botrytis cinerea suspended in peptone water and irradiated with PL (fluence = 1.2 to 47.8 J/cm2) were investigated by using conventional plate count technique, flow cytometry analysis (FCM) and transmission electron microscopy. In addition, PL effect on B. cinerea development in artificially contaminated strawberries throughout storage at (5 ±â€¯1) °C was evaluated. PL reduced fungus' ability to form colonies on agarized culture media. Survival curve fitted with the Weibullian model evidenced a wide distribution of conidia sensitivity to PL. FCM showed that most of irradiated conidia entered in a viable non-culturable state, although a subpopulation without esterase activity and compromised membranes and a subpopulation with active esterase and intact membranes were also detected. PL attacked multiple targets in B. cinerea. Ultrastructural changes varied with the dose and within the conidia population, supporting FCM results. Damage included plasmalemma detachment from cell wall, cytoplasm collapse, and vacuolization of cytoplasm, disruption of cell wall and plasmalemma with massive loss of cytoplasm and/or disruption of organelles. In strawberries artificially contaminated with B. cinerea, a 2-day delay on the onset of the infection and a lower incidence in PL-treated strawberries (11.9 and 23.9 J/cm2) compared to control (16-20%) up to 10 days of cold storage was observed. Results indicated that PL significantly reduces B. cinerea growth in peptone water and in inoculated strawberries. However, other preservation factor(s) in combination would be needed to increase PL action for a better control of this fungus.

Study of the inactivation of spoilage microorganisms in apple juice by pulsed light and ultrasound.

The aim of this study was to evaluate the effect of ultrasound (US) (600 W, 20 kHz and 95.2 µm wave amplitude; 10 or 30 min at 20, 30 or 44 ± 1 °C) and pulsed light (PL) (Xenon lamp; 3 pulses/s; 0.1 m distance; 2.4 J/cm(2)-71.6 J/cm(2); initial temperature 2, 30, 44 ± 1 °C) on the inactivation of Alicyclobacillus acidoterrestris ATCC 49025 spores and Saccharomyces cerevisiae KE162 inoculated in commercial (pH: 3.5; 12.5 °Brix) and natural squeezed (pH: 3.4; 11.8 °Brix) apple juices. Inactivation depended on treatment time, temperature, microorganism and matrix. Combination of these technologies led up to 3.0 log cycles of spore reduction in commercial apple juice and 2.0 log cycles in natural juice; while for S. cerevisiae, 6.4 and 5.8 log cycles of reduction were achieved in commercial and natural apple juices, respectively. In natural apple juice, the combination of US + 60 s PL at the highest temperature build-up (56 ± 1 °C) was the most effective treatment for both strains. In commercial apple juice, US did not contribute to further inactivation of spores, but significantly reduced yeast population. Certain combinations of US + PL kept on good microbial stability under refrigerated conditions for 15 days.

Hurdle technology in fruit processing.

Conventional preservation technologies such as thermal processing ensure the safety and shelf life of fruit-derived products but can result in the loss of physicochemical and nutritional quality attributes. This review examines innovative hurdle techniques to obtain novel fruit products with fresh-like characteristics. The multifactorial processes were based on emerging preservation factors in combination or combining emerging factors with traditional ones. Selected practical examples of fruit processing using UV light, pulsed light (PL), ultrasound (US), and high hydrostatic pressure (HHP) are presented. Some issues of key importance for the design of combination processes are also addressed.

Multi-level approach for the analysis of water effects in corn flakes.

The purpose of this work was to analyze the effect of water on thermal transitions, mechanical properties, and molecular mobility in corn flakes (CF), and their relationships. Commercial common (CCF) and sugar-frosted (SCF) corn flakes were studied in a water content (wc) range from 5 to 20 (% dry basis). The slope of (1)H NMR spin-spin relaxation time T 2* (determined by FID) versus temperature plot changed close to T g. Compression force showed a maximum at wc of ca. 12 and 16% (db) for SCF and CCF, respectively. (1)H NMR complemented DSC data in determining the temperature dependence of water and solid mobility, in order to assess quality of laminated corn products. The results of the present work indicate that while the compression force showed a maximum value as a function of water content, T g values determined by DSC or by spin-spin relaxation decreased progressively with increasing water content.

Aspergillus flavus growth in the presence of chemical preservatives and naturally occurring antimicrobial compounds.

The combined effects of water activity ([a(w)] 0.99 or 0.95), pH (4.5 or 3.5) and antimicrobial agent (potassium sorbate, sodium benzoate, sodium bisulfite, carvacrol, citral, eugenol, thymol, or vanillin) concentration (0, 100, 200 up to 1800 ppm) on the growth of Aspergillus flavus were evaluated in potato dextrose agar (PDA). Mold spore germination time and radial growth rates (RGR) were significantly (p<0.05) affected by the variables. For equal antimicrobial concentration, reduction in pH or a(w) had important effects, lowering RGR and delaying germination time. Depending on a(w) and pH, increase in antimicrobial concentration slightly reduced RGR until a critical concentration where RGR was drastically reduced or mold growth was inhibited. Germination time increased as antimicrobial agent concentration increased and when a(w) and pH decreased. Important antimicrobial differences were observed, being, in general, the natural antimicrobials less pH-dependent than chemical preservatives. A. flavus exhibited higher sensitivity to thymol, eugenol, carvacrol, potassium sorbate, sodium bisulfite, and sodium benzoate (at pH 3.5) than to vanillin or citral.

Aspergillus flavus dose-response curves to selected natural and synthetic antimicrobials.

The effects of selected concentrations of antimicrobials from natural (vanillin, thymol, eugenol, carvacrol or citral) or synthetic (potassium sorbate or sodium benzoate) origin on Aspergillus flavus lag time inoculated in laboratory media formulated at water activity (a(w)) 0.99 and pH 4.5 or 3.5, were evaluated. Time to detect a colony with a diameter > 0.5 mm was determined. Mold response was modeled using the Fermi function. Antimicrobial minimal inhibitory concentration (MIC) was defined as the minimal required inhibiting mold growth for 2 months. Fermi function successfully captured A. flavus dose-response curves to the tested antimicrobials with a highly satisfactory fit. Fermi equation coefficients, Pc and k, were used to compare antimicrobials and assess the effect of pH. Important differences in Pc and k were observed among antimicrobials, being natural antimicrobials less pH dependent than synthetic antimicrobials. A large Pc value represents a small antimicrobial effect on A. flavus lag time; thus, high concentrations are needed to delay growth. A. flavus exhibited higher sensitivity to thymol, eugenol, carvacrol, potassium sorbate (at pH 3.5), and sodium benzoate (at pH 3.5) than to vanillin or citral. MICs varied from 200 ppm of sodium bcnzoate at pH 3.5 to 1800 ppm of citral at both evaluated pHs.