•UAE is an efficient method to obtain betalains and polyphenols with high AA.•BT, BC, BX, TP, AA, b*, KLa, and A were affected by temperature and UPD.•Optimal UAE conditions were 41.80 °C and 188.84 ...mW/mL.•Optimal conditions showed that BC, BX, BT, TP, AA, L*, a*, b*, KLa, A, and IA agreed with predicted values.
The present study optimised the ultrasound-assisted extraction (UAE) of bioactive compounds from Amaranthus hypochondriacus var. Nutrisol. Influence of temperature (25.86–54.14 °C) and ultrasonic power densities (UPD) (76.01–273.99 mW/mL) on total betalains (BT), betacyanins (BC), betaxanthins (BX), total polyphenols (TP), antioxidant activity (AA), colour parameters (L*, a*, and b*), amaranthine (A), and isoamaranthine (IA) were evaluated using response surface methodology. Moreover, betalain extraction kinetics and mass transfer coefficients (KLa) were determined for each experimental condition. BT, BC, BX, TP, AA, b*, KLa, and A were significantly affected (p < 0.05) by temperature extraction and UPD, whereas L*, a*, and IA were only affected (p < 0.05) by temperature. All response models were significantly validated with regression coefficients (R2) ranging from 87.46 to 99.29%. BT, A, IA, and KLa in UAE were 1.38, 1.65, 1.50, and 29.93 times higher than determined using conventional extraction, respectively. Optimal UAE conditions were obtained at 41.80 °C and 188.84 mW/mL using the desired function methodology. Under these conditions, the experimental values for BC, BX, BT, TP, AA, L*, a*, b*, KLa, A, and IA were closely related to the predicted values, indicating the suitability of the developed quadratic models. This study proposes a simple and efficient UAE method to obtain betalains and polyphenols with high antioxidant activity, which can be used in several applications within the food industry.
•UV-C irradiation was identified as an alternative way of Aloe vera gel processing.•Thermal treatment (TT) affected simple sugar content more than UV-C irradiation.•In contrast to TT, UV-C ...irradiation did not strongly affect molecular weight.•TT resulted in more pronounced deacetylation of acemannan than UV-C irradiation.•Acemannan quantification was performed by 1H NMR.
The effects of pH (3.5, 4.5, and 5.5) and UV-C irradiation dose (12.8, 24.2, 35.8, and 54.6 mJ/cm2) on the physicochemical properties changes in 10% Aloe vera gel blends; in addition, the acemannan concentration and structural changes in the precipitated polysaccharides were evaluated. A thermal treatment (TT; 45 s at 90 °C) was used for comparison. In contrast to TT, a dose of 24.2 mJ/cm2 did not induce significant changes of free sugar content. Moreover, TT and UV-C irradiation did not significantly affect the content of mannose but increased those of galactose, fructose, and glucose. 1H NMR analysis revealed minimal changes in the isolated fractions of acemannan, indicating that compared to the unprocessed control sample, the acemannan deacetylation was more pronounced by TT (27%) than by UV-C irradiation (11% at 54.6 mJ/cm2), without any significant difference between the two. UV-C irradiation of Aloe vera gel blends at pH 3.5 and 24.2 mJ/cm2 was an alternative to TT and efficiently preserve the characteristics of acemannan.
Physicochemical properties of a blend of 10%
gel with 5% pitaya juice subjected to UV-C doses of 16.5, 27.7, and 40 mJ/cm
were evaluated at pH 3.5 and 5.5. Unprocessed treatments were used as the ...control. The
* color parameter decreased and luminosity increased at pH 3.5. The decrease in the reddish color was consistent with the decrease in total betalains content and stabilized at pH 5.5. The NMR analyses of UV-C treatments showed changes in betalains signal patterns. Polyphenolics content was significantly reduced in the UV-C treatments at pH 5.5. UV-C processing decreased the antioxidant activity 1.25 times compared to unprocessed treatments. Total sugar content was reduced as the UV-C dose increased. Doses above 16.5 mJ/cm
resulted in a higher simple sugar content at a pH 3.5. The UV-C continuous flow technology can be applied to stabilize betalains in
-pitaya blends at a UV-C dose of 16.5 mJ/cm
and pH 5.5.
We evaluated the effects of solvents with different polarities—methylene chloride (MC), methanol (MT), and hexane (HE) on the extraction of compounds from Mexican red pitaya seed oil. The fatty acid ...composition and the structural, rheological, and thermal properties of the different extracts were characterized. The results indicated that the highest yield of extraction was generated for MC (26.96%), as well as the greatest amount of Mono and Polyunsaturated fatty acids, while the lowest yield was for MT (16.86%). The antioxidant activity was greater in the MT treatment due to extractable compounds from high polarity. The generated extracts contained unsaturated fatty acids, mostly oleic and linoleic acids, and saturated fatty acids such as palmitic acid. The lowest solidification temperature was −6.35 ℃ for MC due to its fatty acid composition, and the degradation temperature was around 240 ℃. The viscosity is a quality parameter; the highest level was generated for the MC treatment, which was significantly different from HE and MT. The composition of the extracts was analyzed using the FT-IR spectroscopy and showed the typical characteristic of absorption bands for triglycerides with high frequency in bands 2852 cm −1 and 2924 cm −1 , which indicated that the samples were rich in unsaturated and polyunsaturated acids. These results suggested that pitaya seed oil is an excellent alternative source of essential fatty acids with potential physiological benefits.
Effects of agave fructans as carrier agents on the encapsulation of blue corn anthocyanins using spray-drying were evaluated. Blue corn extract was mixed with 6%, 8%, 10%, and 12% (
/
) of agave ...fructans in duplicate and dried at 150 °C. The extract showed good contents of anthocyanins, polyphenols, and antioxidant activity. The increase of agave fructans in the encapsulated powders caused a significant increase (
< 0.05) in the humidity, water activity (a
), pH, bulk density, water solubility index (WSI), and color
* values. On the contrary, the agave fructan addition decreased the hygroscopicity, water absorption index (WAI), antioxidant activity, total anthocyanin, total polyphenol, and individual anthocyanin contents. The encapsulation of blue corn extract with 6% agave fructans (
/
) resulted in good physical, thermal, morphological, and high antioxidant properties. The results suggest that the use of agave fructans as wall material represents advantages in the conservation of anthocyanins and other bioactive compounds from blue corn extract during their encapsulation. The application of blue corn anthocyanin encapsulated powders as a food ingredient is promising for food pigmentation, representing additional advantages for their contribution as a soluble fiber that can benefit the health of consumers.
Fusarium species belonging to the Fusarium fujikuroi species complex (FFSC) are associated with maize in northern Mexico and cause Fusarium ear and root rot. In order to assess the diversity of FFSC ...fungal species involved in this destructive disease in Sinaloa, Mexico, a collection of 108 fungal isolates was obtained from maize plants in 2007–2011. DNA sequence analysis of the calmodulin and elongation factor 1α genes identified four species: Fusarium verticillioides, F. nygamai, F. andiyazi and F. thapsinum (comprising 79, 23, 4 and 2 isolates, respectively). Differential distribution of Fusarium species in maize organs was observed, that is F. verticillioides was the most frequently isolated species from maize seeds, while F. nygamai predominated on maize roots. Mixed infections with F. verticillioides/F. thapsinum and F. verticillioides/F. nygamai were detected in maize seeds and roots, respectively. Pathogenicity assay demonstrated the ability of the four species to infect maize seedlings and induce different levels of disease severity, reflecting variation in aggressiveness, plant height and root biomass. Isolates of F. verticillioides and F. nygamai were the most aggressive. These species were able to colonize all root tissues, from the epidermis to the vascular vessels, while infection by F. andiyazi and F. thapsinum was restricted to the epidermis and adjacent cortical cells. This is the first report of F. nygamai, F. andiyazi and F. thapsinum infecting maize in Mexico and co‐infecting with F. verticillioides. Mixed infections should be taken into consideration due to the production and/or accumulation of diverse mycotoxins in maize grain.
Mycobacterium tuberculosis and M. smegmatis form drug-tolerant biofilms through dedicated genetic programs. In support of a stepwise process regulating biofilm production in mycobacteria, it was ...shown elsewhere that lsr2 participates in intercellular aggregation, while groEL1 was required for biofilm maturation in M. smegmatis. Here, by means of RNA-Seq, we monitored the early steps of biofilm production in M. bovis BCG, to distinguish intercellular aggregation from attachment to a surface. Genes encoding for the transcriptional regulators dosR and BCG0114 (Rv0081) were significantly regulated and responded differently to intercellular aggregation and surface attachment. Moreover, a M. tuberculosis H37Rv deletion mutant in the Rv3134c-dosS-dosR regulon, formed less biofilm than wild type M. tuberculosis, a phenotype reverted upon reintroduction of this operon into the mutant. Combining RT-qPCR with microbiological assays (colony and surface pellicle morphologies, biofilm quantification, Ziehl-Neelsen staining, growth curve and replication of planktonic cells), we found that BCG0642c affected biofilm production and replication of planktonic BCG, whereas ethR affected only phenotypes linked to planktonic cells despite its downregulation at the intercellular aggregation step. Our results provide evidence for a stage-dependent expression of genes that contribute to biofilm production in slow-growing mycobacteria.
•Ultrasound treatment increased the extraction of water soluble carbohydrates from agave.•Ultrasound treatment at low temperatures resulted in significant fructan extraction.•Thermal and ultrasound ...treatment caused agave cell-wall disruption.•Mass transfer parameters were increased mainly by the sonication treatment.•A general model to predict the fructans ultrasound-assisted extraction was developed.
The effect of ultrasound power and temperature on the extraction of carbohydrates from agave was evaluated. Extraction kinetics of fructans (F), total carbohydrates (TC) and reducing sugars (RS) were obtained at different ultrasound powers (28–49mW/mL) and temperatures (20–40°C). The mass transfer coefficients of F, TC and RS were calculated and a model using the production functions of Cobb–Douglas was developed. Microstructural analysis was performed to evaluate the effect of ultrasound and temperature on carbohydrates extraction. Ultrasound and temperature had impact on F, TC and RS extractions. After 5min, no increases in carbohydrates content were observed, showing an asymptotic tendency. Results showed a strong sonication effect in carbohydrate extraction at any extraction temperature. The maximum F, TC and RS contents were 7.2, 7.79 and 0.54g/100gd.m., respectively, at 49mW/mL and 40°C. The fructans volumetric mass transfer coefficients ranged from 0.0585±4.2×10−4 to 0.0834±12.51×10−4s−1 (R2=0.86–0.92). An overall model was developed based on the Cobb–Douglas function, which was adjusted adequately to estimate the fructans extraction assisted with ultrasound (R2=0.954). Tissue structural changes were present due to cell-wall modifications and breakdowns of sonicated agave samples, which have enhanced the carbohydrates extraction.
Climate change can impair ecosystem functions and services in extensive dry forests worldwide. However, attribution of climate change impacts on tree growth and forest productivity is challenging due ...to multiple inter-annual patterns of climatic variability associated with atmospheric and oceanic circulations. Moreover, growth responses to rising atmospheric CO2, namely carbon fertilization, as well as size ontogenetic changes can obscure the climate change signature as well. Here we apply Structural Equation Models (SEM) to investigate the relative role of climate change on tree growth in an extreme Mediterranean environment (i.e., extreme in terms of the combination of sandy-unconsolidated soils and climatic aridity). Specifically, we analyzed potential direct and indirect pathways by which different sources of climatic variability (i.e. warming and precipitation trends, the North Atlantic Oscillation, NAO; the Mediterranean Oscillation, MOI; the Atlantic Mediterranean Oscillation, AMO) affect aridity through their control on local climate (in terms of mean annual temperature and total annual precipitation), and subsequently tree productivity, in terms of basal area increments (BAI). Our results support the predominant role of Diameter at Breast Height (DHB) as the main growth driver. In terms of climate, NAO and AMO are the most important drivers of tree growth through their control of aridity (via effects of precipitation and temperature, respectively). Furthermore and contrary to current expectations, our findings also support a net positive role of climate warming on growth over the last 50 years and suggest that impacts of climate warming should be evaluated considering multi-annual and multi-decadal periods of local climate defined by atmospheric and oceanic circulation in the North Atlantic.
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•The NAO and the AMO are the most important climatic drivers of growth.•Climate warming represents one third of the climatic variability in this area.•Climate warming has had a net positive influence on tree growth.•There is no evidence of precipitation tendencies or carbon fertilization.
The effects of UV-C irradiation (at doses of 8.16, 10.93, 16.17, and 33.29 mJ/cm2) on the physicochemical and microbiological properties of Agave tequilana Weber extracts at various pH values (4.5, ...5.5, and 6.5) were evaluated. Thermal treatment (TT) was used as a control (85 °C for 30 s). Both processed (UV-C or TT) and unprocessed (UP) extracts were investigated. The UV-C dose and the pH significantly (p < 0.05) affected the inactivation of total coliforms (TC), total aerobic mesophiles (TAM), and yeasts and molds (YM). UV-C doses of 10.93 mJ/cm2 at pH 4.5 and 33.29 mJ/cm2 at any agave extract pH completely inactivated the native microbial load compared to TT. The total polyphenols (TP), antioxidant activity (AA), and sugar content did not change in the agave extracts at any dose, but the total flavonoid (TF) content decreased at doses > 16.17 mJ/cm2 at the evaluated pH values. Although the color of the agave extracts (L*, a*, and b*) was significantly affected, the total color difference (∆E) did not change after processing compared to the ∆E in the UP extracts. TT further reduced all the physicochemical properties of the agave extracts compared to UV-C processing. The results suggest that UV-C continuous flow technology can be used to stabilize agave extracts at doses of 10.93 mJ/cm2 and pH 4.5, while preserving their functional properties.
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