Doses and ratio of linoleic acid (LA) and α-linolenic acid (ALA) preventing metabolic syndrome (MS) were investigated. SD rats were fed (i) basal diet, (ii) high-fructose and high-fat diet (HFFD), (iii) HFFD with increasing-dose LA (0.75 energy-% ALA + 3, 6, 9, 12, 15, and 30 energy-% LA), and (iv) HFFD with increasing-dose ALA (6 energy-% LA + 0.3, 0.5, 0.75, 1.5, 2.25, and 3.75 energy-% ALA) for 18 weeks. Results showed 6, 12, 15, and 30 energy-% LA significantly ameliorated central obesity, hyperlipidemia, glucose homeostasis, and leptin status; 0.5 and 0.75 energy-% ALA significantly improved insulin sensitivity, adiponectin, and anti-inflammatory status. Moreover, high intakes of ALA (1.5, 2.25, and 3.75 energy-%) presented a pro-oxidant activity. In conclusion, dose instead of ratio determines the prevention of MS. The optimal doses are 6 energy-% LA and 0.75 energy-% ALA; high intakes of ALA may have side effects.

The lipid peroxidation of unsaturated fatty acids (UFAs) in the retina not only threatens visual cells but also affects the physiological health of the retina. In this work, the potential damages caused by daily visible light exposure on retinal UFAs were evaluated via a simulated in vitro model. At the same time, the benefits of dietary supplementation of blueberries to the eyes were also assessed. After prolonged light exposure, lipid peroxidation occurred for both docosahexaenoic and arachidonic acids (DHA and AA, respectively). The oxidized UFAs presented obvious cytotoxicity and significantly inhibited cell growth in retinal pigment epithelium cells. Among the different blueberry polyphenol fractions, the flavonoid-rich fraction, in which quercetin was discovered as the main component, was considerably better in preventing visible light-induced DHA lipid peroxidation than the anthocyanin- and phenolic acid-rich fractions. Then the retinal protective activity of blueberry polyphenols against light-induced retinal injury was confirmed in vivo. On the basis of the above results, inhibiting lipid peroxidation of UFAs in the retina is proposed to be another important function mechanism for antioxidants to nourish eyes.

Highlights•Cellular antioxidant activity assay (CAA) using oleic acid as stressor is developed.•Oleic acid promotes oxidative stress without causing the decrease of cell viability.•EGCG is the best ROS inhibitor among 16 flavonoids in CAAoleic acid assay.•The CAAoleic acid assay is probably more biological relevant than the CAAAAPH assay.The existing cellular antioxidant activity (CAA) assays always use chemical stressors [e.g. 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH)] to initiate oxidative stress (OS), which is not accordance with the pathology of OS-related diseases. In contrast to previous cell models, an oleic acid (OA)-induced OS model of the HepG2 cells was developed in the current work. The antioxidant activities (AAs) of the 16 flavonoid standards in the CAAOA assay were significantly different from the results of the CAAAAPH and peroxyl radical-scavenging assays (PRSA). The AAs of these flavonoids in the PRSA were significantly associated with those of the CAAAAPH assay (r = 0.848, P < 0.01). On the other hand, isoflavones and epicatechin could significantly attenuate the OS in the CAAOA assay. However, the three flavonoids had no quantifiable AA in CAAAAPH and PRSA. The aforementioned results suggest that the CAAOA assay can probably better reflect the AAs of samples in biological systems.

Studies suggest that the consumption of berry fruits rich in anthocyanins may have beneficial effects on improving visual function. This study determined the total polyphenol and total anthocyanin contents in wild Chinese blueberries using the Folin−Ciocalteu reagent method and a pH differential method. Anthocyanin composition and quantity were characterized by high-performance liquid chromatography−electrospray ionization−tandem mass spectrometry coupled with mass selective detection. Total polyphenol and anthocyanin contents were 602.9 ± 9.2 and 177.8 ± 8.3 mg/100 g, respectively. Seventeen anthocyanins were discovered, and only 13 were tentatively identified in the wild blueberries. Anthocyanins of malvidin glycosylated with hexose or pentose accounted for >46% of total anthocyanin content. Furthermore, the effect of whole blueberries on retinal damage in pigmented rabbits upon light exposure was investigated, and the retinal functions were evaluated by electroretinogram (ERG). Pigmented rabbits were chosen for this experiment because of their large eyes, which facilitated the operative procedure and observation, and the similarity of their eyes to the human eye structure. Light-induced retinal damage was induced by exposure to white light at 15000 ± 1000 lx for 2 h. Feeding the rabbits with blueberries at a dosage of 1.2 or 4.9 g/kg/day for 4 weeks prior to light exposure effectively reduced photodamage to the retinas. This study adds to the growing body of data supporting the bioactivity of blueberries in improving mammal vision.

Gluconacetobacter sp. A4 (G. sp. A4), which had strong ability to produce d-saccharic acid 1, 4 lactone (DSL), was the key functional bacteria isolated from the kombucha preserved. This paper investigated the interaction between G. sp. A4 and ten different strains of lactic acid bacteria (LAB) obtained from kefir. The result suggested that the LAB promoted DSL production of G. sp. A4 to different extents, ranging from 4.86% to 86.70%. Symbiosis between G. sp. A4 and LAB was studied. LAB’s metabolites, xylitol, and acetic acid, were utilized by G. sp. A4, and it promoted the growth of G. sp. A4 and yield of DSL. Therefore, in developing starter cultures for kombucha fermentation process, a mixed flora of LAB and G. sp. A4 would be the optimal combination.

Fresh apple juice was heated at 95 °C for 30 and 60 min, and then stored for 6 days for obtaining different extent of non-enzymatic browning. Front-face fluorescence excitation–emission-matrix (EEM) with excitation at 355 and 400 nm and emission ranges of 385–600, and 430–600 nm was used to measure the juice samples. The sign test pointed out an enhanced sensitivity of EEM compared to commonly used browning indicators, such as non-enzymatic browning index (NEBI), color readings in L∗a∗b∗ space, and the concentration of 5-hydroxymethylfurfural (HMF). Using the fluorescence data, the correctness of classifications of fresh juice, heated juice, and stored juice were >85%. Multivariate analyses were applied to study the relations of fluorescence emission spectra and common indicators. For predicting NEBI, b∗, and HMF, the correlation coefficients were >0.80. Resulting, the spectroscopic analyses of fluorescent neoformed products such as HMF provide a feasible approach to monitor non-enzymatic browning of juice.

The ν-support vector regression (ν-SVR) was used to construct the calibration model between soluble solids content (SSC) of apples and acousto-optic tunable filter near-infrared (AOTF-NIR) spectra. The performance of ν-SVR was compared with the partial least square regression (PLSR) and the back-propagation artificial neural networks (BP-ANN). The influence of SVR parameters on the predictive ability of model was investigated. The results indicated that the parameter ν had a rather wide optimal area (between 0.35 and 1 for the apple data). Therefore, we could determine the value of ν beforehand and focus on the selection of other SVR parameters. For analyzing SSC of apple, ν-SVR was superior to PLSR and BP-ANN, especially in the case of fewer samples and treating the noise polluted spectra. Proper spectra pretreatment methods, such as scaling, mean center, standard normal variate (SNV) and the wavelength selection methods (stepwise multiple linear regression and genetic algorithm with PLS as its objective function), could improve the quality of ν-SVR model greatly.

The root of Platycodon grandiflorum (Jacq.) A. DC has been reported to have a wide range of health benefits in oriental food. This study examined the hypoglycemic effects of Platycodon grandiflorum (Jacq.) A. DC aqueous-ethanol extract (PGE) in streptozotocin (STZ) -induced diabetic ICR mice (STZ diabetic mice) for the first time. The effects of PGE on blood glucose, plasma insulin levels and body weight were investigated. A significant decrease in blood glucose levels was observed after single administration of PGE. Furthermore, Glibenclamide and PGE significantly suppressed the rise in blood glucose after 30 min in the acute glucose tolerance test. Treatment with glibenclamide and PGE resulted in a reduction in blood glucose levels from the 2nd week, and this reduction was maintained until the 4th week of treatment. The body weight changed slightly in glibenclamide and PGE treated mice in comparison with the STZ control group. Plasma insulin levels were increased with glibenclamide treatment in STZ diabetic mice, whereas such effect was not observed with PGE. These results indicated that PGE could induce hypoglycemic effects without stimulating insulin secretion.

Laser-induced light backscattering imaging was studied regarding its potential for analyzing apple soluble solids content (SSC) and fruit flesh firmness. Images of the backscattering of light on the fruit surface were obtained from ‘Elstar’ and ‘Pinova’ apples using laser diodes emitting at five wavelength bands. Image processing algorithms were tested to correct for dissimilar equator and shape of fruit. Particularly the frequencies of gray scale intensities obtained for selected wavelengths were used for the first time to calibrate on the fruit firmness and SSC using partial least squares regression. Calibration with highest performance for predicting ‘Elstar’ SSC was based on the corrected intensity frequency of raw data set with correlation coefficient of r = 0.89 and standard error of cross validation %SECV = 4.14. For evaluating ‘Elstar’ flesh firmness, corrected frequency gave the highest r = 0.90, and %SECV = 5.49. An inter-cultivar test-set validation of the method resulted in SEP < 13% for SSC and firmness prediction.

Monitoring of apple fruit development is necessary to determine appropriate production measures. Furthermore, consumer acceptance of apples depends on internal quality especially regarding the soluble solids content (SSC) and fruit flesh firmness. In the present work, laser-induced light backscattering imaging was applied to analyze fruit SSC and firmness during apple development in different growing locations by means of non-destructive readings, showing potential for rapid site-specific fruit evaluation during production. Spectral images of the backscattering of light on the fruit surface were obtained from ‘Elstar’ and ‘Pinova’ apples using laser diodes emitting at five wavelengths (10 nm bandpass) between 600 and 1100 nm, addressing the fruit absorption and scattering properties. Different multivariate calibration methods were tested on the frequency of different intensities of backscattering each for the five wavelength bands to analyze SSC and firmness. The method was applied on two cultivars picked at weekly intervals during fruit development grown in sites with different plant water availability. During fruit development the mean values of SSC data of drought stressed and sufficiently irrigated regions of orchard ranged from 11.1 to 15.4 and 10.5 to 14.5 °Brix, respectively. The mean values of fruit firmness at the two different field regions developed from 130.9 to 71.6 and 116.1 to 68.3 N/cm2, respectively.Using partial least squares regression, calibration uncertainty in cross-validation ranged between 6 and 2% for SSC and firmness, while a validation on a test-set gave a percentage error of prediction in the range of 10% for SSC and 9% for firmness with respect to refractometrical SSC readings and the Magness–Taylor firmness test, respectively. Variation in fruit parameters due to slight drought stress was found in the range of 12–13%. A calibration on the specific fruit material is necessary for assessing the spatial distribution of fruit quality parameters in the orchard, however, laser-induced backscattering imaging is an inexpensive method for rapidly receiving relevant information for site-specific measures.

Traditionally, the direct orthogonal signal correction (DOSC) is always used together with a latent variable method such as partial least square (PLS) or principal component regression (PCR), to build a linear calibration model. In this study, PLS and least square support vector machine (LSSVM) were used to develop the linear and non-linear relation between spectra and components, respectively. DOSC was used to preprocess the input data, and the effect of DOSC pretreatment on linear and non-linear calibration model was investigated. The experiment was performed with three data sets. The first one was the acousto-optic tunable filter near infrared (AOTF-NIR) spectra of apples, the second one was the temperature-induced spectra of a ternary mixture of ethanol, water and 2-propanol, and the third one was the NIR spectra of corn. For all of the applications, the relation between spectra and components can be clearly observed in the spectra plot or the score plot after DOSC pretreatment. DOSC improved the predictive ability of PLS model. However, DOSC removed useful non-linear information that was related to components, thus, was not able to improve the performance of LSSVM model. DOSC pretreatment seems to be not suitable for non-linear calibration.