Soluble sugar and organic acid composition and flavor evaluation of Chinese cherry fruits

Chinese cherry is an economically important fruit crop native to China. Flavor quality is greatly influenced by compositions of soluble sugars and organic acids. To better understand the flavor quality of Chinese cherry, we determined sugar and acid components in thirty-eight landrace and cultivar collections, and two wild resources using the HPLC method. Glucose and fructose were the main components, accounting for 85.91% of soluble sugars. Malic acid was the predominant organic acid, with an average proportion of 65.73% of total acids. Correlation and PCA analysis revealed seven key indicators for evaluating fruit flavor. Compared with wild Chinese cherry, the cultivated collections exhibited higher levels of soluble sugars, especially fructose, and lower levels of organic acid, particularly malic acid in fruits. Finally, we have established grading criteria for seven flavor indicators in Chinese cherry. Our study provides valuable references for identifying flavor compounds and improving flavor quality of Chinese cherry.

Dynamics of microbial communities, flavor, and physicochemical properties of pickled chayote during an industrial-scale natural fermentation: Correlation between microorganisms and metabolites

Pickled chayote is a Chinese fermented vegetable with unique flavors and is favored by local consumers. However, little is known about its quality changes and microbial community succession during fermentation and the relationship between microbes and quality. In the work, the physicochemical quality attributes (pH, acidity, nitrite, texture, and color) and flavor properties (sugars, organic acids, free amino acid [FAA], and volatiles) were investigated. The results revealed that organic acids, FAAs, and key volatiles (esters, terpenes, alcohols, and phenols) significantly increased during fermentation. Lactobacillus was the dominant bacterial genus with Lactobacillus alimentarius being the prevalent species; Kazachstania and Pichia were dominant fungal genera with Kazachstania humilis and Pichia membranifaciens being the prevalent species. The microbial metabolic network found that bacteria (L. alimentarius, L. futsaii, and L. paralimentarius) and fungi (K. humilis and P. membranifaciens) played significant roles in the physicochemical changes and flavor production of pickled chayote.

Effect of centrifugal pre-treatment on flavor change of cloudy orange juice: Interaction between pectin and aroma release

Cloud loss of orange juice could be effectively inhibited by centrifugal treatment, but it can induce flavor changes, which become a new challenge for the industry. This work aims to investigate the effect of centrifugation on flavor changes in orange juice and explore its possible mechanism. Taste- and aroma-related attributes were analyzed, and pectin was characterized. Results indicated that pH (4.00), total soluble solid (9.67 °Brix), titratable acidity (0.42%), sucrose (44%), fructose (29%), and glucose (27%) were less affected by centrifugation (P > 0.05). However, aroma compounds significantly changed (P < 0.05), where terpenes and alcohols tended to be distributed in pulp and serum after centrifugation, respectively. Pearson correlation analysis showed that aroma compound distribution induced by centrifugation was highly related to chelator-solubilized pectin fraction and sodium carbonate-solubilized pectin fraction (|R| > 0.9). In general, centrifugation clearly changed aroma of orange juice, which was mainly affected by pectin characteristics.

Composition and structural characterization of pectin in micropropagated and conventional plants of Premma puberula Pamp

The metabolites produced by plants can be enhanced by plant tissue culture. In Premma puberula Pamp., the pectin content in leaves is 30 %-40 %, and it is widely used in the food industry and medicine. However, inefficient propagation has seriously restricted the utilization of pectin resources. Therefore, we established an efficient micropropagation technology for P. puberula through comparative analysis in mature leaves of regenerated and conventionally propagated plants. The results showed that the pectin composition of their leaves was similar in terms of galacturonic acid, monosaccharide composition, degree of esterification, functional groups, nuclear magnetic resonance spectrum and morphological characteristics. Furthermore, micropropagated plants had better hardness, gumminess and chewiness characteristics than conventionally propagated plants and were similar in emulsion stability, adhesiveness, springiness, cohesiveness and viscoelasticity. Therefore, micropropagation technology will provide an important guarantee for the industrial production of pectin from P. puberula. The technical essentials include callus induction, embryoid formation, and root induction, followed by acclimatization and transplanting.

Ratiometric fluorescent sensing carbendazim in fruits and vegetables via its innate fluorescence coupling with UiO-67

A ratiometric fluorescent sensor was facilely fabricated using innate fluorescence of carbendazim (MBC) and fluorescent UiO-67 to sensitively and selectively detect MBC in food matrixes. The innate fluorescence of MBC provided a signal at 311 nm (F₃₁₁), and the fluorescent UiO-67 at 408 nm (F₄₀₈) could recognize MBC through π-π stacking inducing fluorescent quenching relied on photoelectron transfer (PET). The ratio (F₃₁₁/F₄₀₈) of the fluorescence enhancement of MBC and the quenching of UiO-67 linearly responded to the MBC concentrations of 0-47.6 μmol/L with a low limit of detection (LOD) of 3.0 × 10^-3 μmol/L. The reverse response signals of the sensor enhanced the sensitivity toward MBC and presented remarkable anti-interference capability in complex matrices. The as-prepared sensor was applied to detect MBC residues in apple, cucumber and cabbage, obtaining satisfactory accuracy and precision with the recovery of 90.82-103.45% and RSDs of lower than 3.03%.

Opportunities for fraudsters: When would profitable milk adulterations go unnoticed by common, standardized FTIR measurements?

Milk is regarded as one of the top food products susceptible to adulteration where its valuable components are specifically identified as high-risk indicators for milk fraud. The current study explores the impact of common milk adulterants on the apparent compositional parameters of milk from the Dutch market as measured by standardized Fourier transform infrared (FTIR) spectroscopy. More precisely, it examines the detectability of these adulterants at various concentration levels using the compositional parameters individually, in a univariate manner, and together in a multivariate approach. In this study we used measured boundaries but also more practical variance-adjusted boundaries to set thresholds for detection of adulteration. The potential economic impact of these adulterations under a milk payment scheme is also evaluated. Twenty-four substances were used to produce various categories of milk adulterations, each at four concentration levels. These substances comprised five protein-rich adulterants, five nitrogen-based adulterants, seven carbohydrate-based adulterants, six preservatives and water, resulting in a set of 360 samples to be analysed. The results showed that the addition of protein-rich adulterants, as well as dicyandiamide and melamine, increased the apparent protein content, while the addition of carbohydrate-based adulterants, whey protein isolate, and skimmed milk powder, increased the apparent lactose content. When considering the compositional parameters univariately, especially protein- and nitrogen-based adulterants did not raise a flag of unusual apparent concentrations at lower concentration levels. Addition of preservatives also went unnoticed. The multivariate approach did not improve the level of detection. Regarding the potential profit of milk adulteration, whey protein and corn starch seem particularly interesting. Combining the artificial inflation of valuable components, the resulting potential profit, and the gaps in detection, it appears that the whey protein isolates deserve particular attention when thinking like a criminal.

A new engineered endo-inulinase with improved activity and thermostability: Application in the production of prebiotic fructo-oligosaccharides from inulin

To construct a high-performance engineered endo-inulinase for fructo-oligosaccharides (FOS) production from inulin, an inulin binding module (IBM) was fused into either N- or C-terminal of an endo-inulinase. After heterologous expression, purification and characterization, the C-terminal fusion one (Eninu-IBM) with better activity, thermostability and inulin binding ability was employed for high-temperature in situ inulin hydrolysis in a 10-L fermentor. During this process, Eninu-IBM was first efficiently produced by the yeast cells at 28 °C for 96 h, and subsequently 1600 g unsterilized inulin per liter fermentation liquor was directly supplemented into the bioreactor for FOS production at 60 °C for 2 h. Finally, high purity of FOS (91.4%) were obtained with FOS titer, yield and productivity of 717.3 g/L, 0.912 g_FOS/g_Inulin and 358.6 g/L/h, respectively. The in vitro prebiotic assay indicated that the final FOS products with main polymerization degrees of 3-5 were preferably fermented by beneficial bifidobacteria and lactobacilli.

Impairment of hormone pathways results in a general disturbance of fruit primary metabolism in tomato

Fruit metabolites are regulated by different phytohormones; however, this needs to be investigated. Dynamic metabolite profiling, based on gas chromatography-mass spectrometry, has been conducted on the fruit of tomato cultivar Micro-Tom and its five hormone mutants: dpy, not, dgt, epi and pro. In total, 48 metabolites were quantified, including sugars, organic acids and amino acids. The results demonstrated that ABA had a greater effect on the regulation of primary metabolism in tomato fruit, while ethylene can play an important role in the transition of primary to secondary metabolism. Besides, results from enzyme activities and transcript abundance involved in primary metabolism suggested that AIV and HXK4 could play key roles in the accumulation of the main sugars. To the best of our knowledge, this is the first comprehensive analysis of the link between hormone and metabolite change during fruit development in a collection of mutants with diverse hormone pathways.

Carbohydrates, volatile and phenolic compounds composition, and antioxidant activity of calabura (Muntingia calabura L.) fruit

Soluble carbohydrates, volatile and phenolic compounds from calabura fruit as well as its antioxidant activity were assessed. The low amount of fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) and similar amount of glucose and fructose allow us to classify the calabura berry as low-FODMAPs. The terpenes β-Farnesene and dendrolasin identified by SPME-GC-MS were the major volatile components. UHPLC-MS/MS analysis revelled gallic acid (5325 μg/g dw) and cyanidin-3-O-glucoside (171 μg/g dw) as the main phenolic compounds, followed by gentisic acid, gallocatechin, caffeic acid and protocatechuic acid. In addition, gallic acid was found mainly in esterified (2883 μg/g dw) and insoluble-bound (2272 μg/g dw) forms. Free and glycosylated forms showed however the highest antioxidant activity due to occurrence of flavonoids (0.28-27 μg/g dw) in these fractions, such as catechin, gallocatechin, epigallocatechin, naringenin, and quercetin. These findings clearly suggest that calabura is a berry with low energy value and attractive colour and flavour that may contribute to the intake of several bioactive compounds with antioxidant activity. Furthermore, this berry have great potential for use in the food industry and as functional food.

Detection of coffee adulteration with soybean and corn by capillary electrophoresis-tandem mass spectrometry

The detection of coffee adulteration with soybean and corn by capillary electrophoresis-tandem mass spectrometry was accomplished by evaluating the monosaccharides profile obtained after acid hydrolysis of the samples. The acid hydrolysis, using H2SO4 as a catalyst, increases the ionic strength of the sample impairing the electrophoretic separation. Therefore, Ba(OH)2 was used to both neutralize the medium and reduce the content of sulfate by precipitation of BaSO4. The best separation of nine determined monosaccharides (fucose, galactose, arabinose, glucose, rhamnose, xylose, mannose, fructose and ribose) plus inositol as internal standard was obtained in 500 mmol·L-1 triethylamine, pH 12.3. The monosaccharides are separated as anionic species at this pH. The proposed method is simple, fast (<12.0 min), present linear calibration curves (r2 = 0.995), and relative standard deviation for replicate injections lower than 5%. The LOQ for all monosaccharides was lower than 0.01 mmol·L-1, which is in accordance with the tolerable limits for coffee. Principal component analysis (PCA) was used to evaluate interrelationships between the monosaccharide profile and the coffee adulteration with different proportions of soybean and corn. Fucose, galactose, arabinose, glucose, sucrose, rhamnose, xylose, mannose, fructose, and ribose were quantified in packed roast-and-ground commercial coffee samples, and differences between adulterated and unadulterated coffees could be detected.

Development of low calorie jams with increased content of natural dietary fibre made from tomato pomace

In this study, four jam formulations were developed, starting with the basic formulation (Jam 1) containing sucrose and without added pectin. Sucrose was partially (50%) replaced by stevioside in formulations of Jam 2 and 3, while in Jam 4 sucrose was completely replaced by fructose and stevioside, making this formulation suitable for diabetic patients. Jam formulations 1 and 2, prepared without added pectin, were thermally stable in the temperature range of 25-90°C, which indicate their potential use as fruit fillings. Jam formulations 3 and 4 were assessed by the sensory panel as more spreadable since tomato pomace particles are incorporated in pectin network which acts as a lubricant. Jam formulations were characterized by a lower total carbohydrate content (17.23-43.81%) and lower energy value (87.1-193.7kcal/100g) when compared to commercial products. Tomato pomace jams contained 15-20 times more dietary fibre than commercial apricot jam.

Chemical characterization and prebiotic activity of fructo-oligosaccharides from Stevia rebaudiana (Bertoni) roots and in vitro adventitious root cultures

Stevia rebaudiana (Bertoni) is widely studied because of its foliar steviol glycosides. Fructan-type polysaccharides were recently isolated from its roots. Fructans are reserve carbohydrates that have important positive health effects and technological applications in the food industry. The objective of the present study was to isolate and characterize fructo-oligosaccharides (FOSs) from S. rebaudiana roots and in vitro adventitious root cultures and evaluate the potential prebiotic effect of these molecules. The in vitro adventitious root cultures were obtained using a roller bottle system. Chemical analyses (gas chromatography-mass spectrometry, (1)H nuclear magnetic resonance, and off-line electrospray ionization-mass spectrometry) revealed similar chemical properties of FOSs that were obtained from the different sources. The potential prebiotic effects of FOSs that were isolated from S. rebaudiana roots enhanced the growth of both bifidobacteria and lactobacilli, with strains specificity in their fermentation ability.

Comparative effects of Aliskiren and Telmisartan in high fructose diet-induced metabolic syndrome in rats. Eur J Pharmacol. 2015;760:145-153. [PMID: 25917321 DOI: 10.1016/j.ejphar.2015.04.019]

Fructose is a commonly used sweetener associated with diets that increase the prevalence of metabolic syndrome (MS). Inhibition of the renin-angiotensin system (RAS) has been consistently demonstrated to reduce MS. However, there has been no direct comparison among different pharmacological modes of inhibiting the RAS concerning their effects on MS. This study investigated the effect of aliskiren, a direct renin inhibitor, versus telmisartan, an angiotensin II-receptor blocker, in the treatment of fructose-induced MS in rats. MS was induced by high fructose (FRC) diet feeding for 12 weeks. Oral administrations of telmisartan (TEL, 5 mg/kg), aliskiren (ALS, 30 mg/kg) or vehicle were started in the last 4 weeks. Results showed that administration of either TEL or ALS with FRC diet equally ameliorated the metabolic parameters (glucose level, oral glucose tolerance test, insulin resistance and serum lipids profile), systolic blood pressure and oxidative stress markers (malondialdehyde, nitric oxide, reduced glutathione levels and catalase activity). Additionally, the effects of TEL and ALS were associated with a decrease in body composition index and attenuation of liver index, serum liver enzyme activities and hepatic expressions of inflammatory and fibrotic markers (tumor necrosis factor-α, nuclear factor kappa-B and transforming growth factor-β) with a significant increase in hepatic glucose transporter-2 and peroxisome proliferator-activated receptors-alpha and gamma expressions. The results suggested that, at indicated dosage, ALS has ameliorative effect equal to that of TEL against FRC-induced metabolic and hepatic disorders; implying that drugs which inhibit the RAS, by different mode of inhibition, profoundly affect fructose-induced MS in rats.

Characterization of an exopolysaccharide produced by Lactobacillus plantarum YW11 isolated from Tibet Kefir

An exopolysaccharide (EPS)-producing strain YW11 isolated from Tibet Kefir was identified as Lactobacillus plantarum, and the strain was shown to produce 90 mgL(-1) of EPS when grown in a semi-defined medium. The molecular mass of the EPS was 1.1 × 10(5)Da. The EPS was composed of glucose and galactose in a molar ratio of 2.71:1, with possible presence of N-acetylated sugar residues in the polysaccharide as confirmed by NMR spectroscopy. Rheological studies showed that the EPS had higher viscosity in skim milk, at lower temperature, or at acidic pH. The viscous nature of the EPS was confirmed by observation with scanning electron microscopy that demonstrated a highly branched and porous structure of the polysaccharide. The atomic force microscopy of the EPS further revealed presence of many spherical lumps, facilitating binding with water in aqueous solution. The EPS had a higher degradation temperature (287.7°C), suggesting high thermal stability of the EPS.

Counter-intuitive effect of non-crystallizing sugars on the crystallization of gemcitabine HCl in frozen solutions

In this study, the effect of four non-crystallizing sugars, namely fructose, trehalose, sucrose and raffinose, was assessed on the crystallization of gemcitabine hydrochloride (GHCl) in frozen solutions. Aqueous solutions containing GHCl (50 mg/mL) and a sugar at varying concentrations (10-60 mg/mL) were frozen in situ in DSC and analyzed in the subsequent heating run. Crystallization propensity of GHCl was quantified in terms of reduced crystallization temperature (RCT) as a function of sugar type and concentration. Multivariate analysis option in JMP(®) software was employed for calculating correlation between the variables. All sugars inhibited GHCl crystallization in a concentration dependent manner. At equal concentration, fructose (with the lowest Tg') exerted the strongest inhibitory effect, whereas raffinose (with the highest Tg') exerted the weakest inhibitory effect. Additionally, RCT showed a poor correlation with Tg' (r=0.2327). Thus, the inhibitory effect of sugars could not be described by their anti-plasticization effect. This counter-intuitive behavior was explained by the inhibitory effect of sugars on ice crystallization, which increased the unfrozen water content (UWC) in the freeze concentrate, thereby lowering the supersaturation of GHCl. This was established by observing a good correlation (r=0.9666) between RCT and ln(1/UWC). Additionally, reduced diffusion kinetics of GHCl in presence of sugar molecules was also postulated. This study highlights the importance of unfrozen water towards governing the crystallization behavior of solutes in multi-component frozen systems.

Inulin crystal initiation via a glucose-fructose cross-link of adjacent polymer chains: atomic force microscopy and static molecular modelling

Semi-crystalline microparticles of inulin (MPI) have clinical utility as potent human vaccine adjuvants but their relevant surface structure and crystal assembly remain undefined. We show inulin crystal surfaces to resemble multi-layered, discoid radial spherulites resulting from very rapid formation of complex tertiary structures, implying directed crystal initiation. Physical and in silico molecular modelling of unit cells confirm steric feasibility of initiation by hydrogen-bonded cross-linking of terminal glucose to a fructose of another chain, mimicking bonding in sucrose crystals. A strong, chelate-like dual H-bond is proposed to compel the known antiparallel alignment of inulin chains. Such cross-linking would require one extra fructose per chain in the native inulin crystal, as observed. Completion of five H-bonded internal ring-domains would 'lock in' each new 6-fructose structural unit of each antiparallel helix pair to create a new isoform. All known properties of inulin isoforms follow readily from these concepts.

Effect of Bridelia ferruginea Benth (Euphorbiaceae) ethyl acetate and acetone fractions on insulin resistance in fructose drinking mice

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Bridelia ferruginea is traditionally used as a treatment for type 2 diabetes. The present study was investigated to evaluate the effect of Bridelia ferruginea root bark fractions on some markers of type 2 diabetes on fructose drinking mice.

MATERIALS AND METHODS

Mice received a solution of fructose 15% during 42 days ad libitum; at the 15th day to the 42nd day, they received distilled water for fructose drinking control group, metformin 50 mg/kg per day or fractions 50 mg/kg per day for treatment groups. The normal control group received only distilled water during the experiment. After 6 weeks of experiment, OGTT, fasting blood glucose, plasma insulin, triglycerides (TG), total cholesterol, AST and ALT levels were measured.

RESULTS

Fructose drinking control group (F) showed significant (p<0.001) increase of glucose tolerance, plasma levels of total cholesterol, triglycerides and insulin index for insulin resistance (Homeostasis Model Assessment ratio HOMA-IR) as compared to normal control mice. In treated groups, there was a significant reduction of glucose intolerance respectively 74% (p<0.001), 25% (p<0.5) and 92% (p<0.001) for ethyl acetate fraction, acetone fraction and metformin at the same dose of 50 mg/kg per day during 4 weeks administration. In ethyl acetate fraction and metformin treated groups, biochemical parameters and insulin index were significantly (p<0.001) lower than that of fructose drinking control group.

CONCLUSIONS

This indicates that Bridelia ferruginea root bark ethyl acetate fraction improved insulin resistance as metformin significantly in type 2 diabetes.