Effects of industrial tomato paste processing on ascorbic acid, flavonoids and carotenoids and their stability over one-year storage

BACKGROUND : The effects of industrial tomato paste processing and long‐term (12 months) ambient storage on the content and stability of quercetin, kaempferol, ascorbic acid (AA), dehydroascorbic acid (DHAA), β‐carotene and lycopene were evaluated in a commercially produced tomato paste. RESULTS : The initial thermal treatment (hot break; 93 °C for 5 min) resulted in significant reductions in quercetin (54%), kaempferol (61%), AA (63%) and β‐carotene (30%), whereas subsequent processing steps (e.g. evaporation and sterilization) did not result in marked changes in these compounds. Lycopene was stable during hot break but decreased by 20% through evaporation and sterilization. The ratio of DHAA:vitamin C increased during hot break to 23%, whereas the ratio of DHAA:vitamin C remained relatively low in subsequent processing steps, indicating that AA was not oxidized. AA decreased with prolonged storage, with only 13% remaining at 12 months. The carotenoids and quercetin remained stable through 12 months of ambient storage. CONCLUSIONS : Tomato pomace contained significant amounts of carotenoids and flavonoids, indicating that it may be an underutilized processing byproduct. Copyright © 2011 Society of Chemical Industry     

NDVI-based land-cover change detection using harmonic analysis

This study presents a normalized difference vegetation index (NDVI)-based land-cover change detection method based on harmonic analysis. Multi-temporal NDVI data show seasonal variation characteristics in the time domain. A harmonic model represents the characterization of the temporal variability in a data set over a local region corresponding to a pixel through its harmonic components. In this research, annual land-cover change detection is performed by tracking the temporal dynamics through analysing harmonic components. A simple but effective noise reduction process is also proposed to provide the necessary high-quality data stream for the multi-temporal NDVI analysis based on the statistics of the observed oscillations. The proposed algorithm was tested and evaluated with the multi-temporal Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI time series of the MYD13Q1, 16 day L3 global 250 m SIN grid (v005) VI data set. The results indicate that the proposed algorithm provides a computationally inexpensive automatic method to monitor vegetation conditions and long-term land-cover change over large regions. The method described here is particularly useful for monitoring changes in well-established deciduous forests with developed canopies.     

Spent coffee as a rich source of antioxidative compounds

Antioxidant activities and major antioxidants were investigated in the methanolic extracts of roasted and spent coffee to evaluate the feasibility of spent coffee as a source of functional ingredients. Phenolic compounds, such as gallic acid, protocatechuic acid, and chlorogenic acid, and nitrogenous compounds, including trigonelline and caffeine, were identified. Caffeine was the most abundant compound, followed by chlorogenic acid. Despite the significant reduction of antioxidants, 2,2,-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was retained in more than 95% of roasted coffee. The retentions of superoxide dismutase (SOD)-like activity and ferric reducing antioxidant power (FRAP) were 65–90 and 46–60%, respectively. Gallic acid had a positive correlation with SOD-like activity, whereas protocatechuic acid positively correlated with FRAP, suggesting that the major compounds contributing to each antioxidant activity are different. These results show that spent coffee can be used as an antioxidant source for functional foods and cosmetic products to improve antioxidant properties.     

Urinary isoflavone excretion in Korean adults: comparisons of fermented soybean paste and unfermented soy flour

BACKGROUND: This study compared the 24 h urinary excretion of isoflavone algycones after the consumption of fermented soybean paste or unfermented soy flour in a population of healthy Koreans (four males and five females). An equivalent amount (20 mg) of total isoflavone was consumed as either 52 g of soybean paste or 12.2 g of soy flour in a randomised, crossover trial consisting of two single‐time‐point feedings and having 3 day run‐in and washout periods between feedings. RESULTS: Analysis of starting materials indicated that daidzein (1.4%) and genistein (1.4%) constituted a smaller proportion of the total isoflavones in soy flour as compared with soybean paste (55.3% daidzein and 45.7% genistein). Free and glycosidic forms of isoflavones differed significantly between the two soy products. Levels of β‐glycosides as well as total glycosides (β‐glycosides, malonyl and acetyl forms) were two‐fold higher in soy flour as compared with soybean paste. Malonyl forms predominated in soy flour. CONCLUSIONS: The consumption of soybean paste resulted in significantly higher urinary excretion of both daidzein and genistein as compared with soy flour (P < 0.05 and P < 0.01 respectively). Copyright © 2007 Society of Chemical Industry     

Mabolizable Energy Differences between Values Calculated Using Energy Conversion Factors and Actual Values Determined by Metabolic Study of Korean Starch Foods

This study was conducted to compare the metabolizable energies of Korean starch foods by an animal metabolic study with those calculated using well‐known energy conversion factors. There were 12 experimental diets (that is, 7 Korean foods, 3 Western foods, and 2 control foods): barley, brown rice, laver‐rolled rice, rice mixed with vegetables and meat, seafood noodle soup, rice cake soup, rice cake in hot pepper paste, pizza, hamburger, spaghetti, basal diet, and glucose. Each diet comprised 70% basal diet and 30% experimental food. After 3 d of adaptation, a metabolic trial was performed for 4 d. The apparent metabolizable energy of pizza, hamburger, spaghetti, and rice cake soup were significantly higher than that of the basal diet group (P < 0.05). For barley, brown rice, laver‐rolled rice, rice mixed with vegetables and meat, and seafood noodle soup, the differences between the actual and calculated energies were 8.7%, 13.3%, 4.5%, 17.2%, and 4.1%, respectively, and the actual energy contents were lower than those calculated using the Atwater conversion factor. The results of this study show that the energy contents of Korean foods are significantly different from those calculated using the conversion factors based on the food composition. Therefore, because Korean starch foods are considered to be calorie‐rich based on calculations, their energy contents can be accurately determined only by animal experiments.     

Experimental Results on a 1.5 MW, 110 GHz Gyrotron with a Smooth Mirror Mode Converter

We present an internal mode converter (IMC) design for a 1.5 MW, 110 GHz gyrotron operating in the TE_22,6 mode. The launcher, designed using the codes Surf3d and LOT, converts the cavity waveguide mode into a nearly pure Gaussian beam. The Gaussian beam output from the launcher is shaped by a series of 4 smooth, curved mirrors to provide a circular output beam with a flat phase front at the gyrotron window. By employing smooth mirrors rather than mirrors with phase correcting surfaces, such an IMC is less sensitive to alignment issues and can more reliably operate with high efficiency. The IMC performance was verified by both cold test and hot test experiments. Beam pattern measurements in each case were in good agreement with theoretical predictions. The output beam was of high quality with calculations showing that the Gaussian Beam content was 95.8 ± 0.5% in both hot and cold test.     

Highly Improved Photocurrent Density and Efficiency of Perovskite Solar Cells via Inclined Fluorine Sputtering Process (Adv. Funct. Mater. 25/2023)

Increase in incident light and surface modification of the charge transport layer are powerful routes to achieve high-performance efficiency of perovskite solar cells (PSCs) by improving the short-circuit current density (J_SC) and charge transport characteristics, respectively. However, few techniques are studied to reduce reflection loss and simultaneously improve the electrical performance of the electron transport layer (ETL). Herein, an inclined fluorine (F) sputtering process to fabricate high-performance PSCs is proposed. The proposed process simultaneously implements the antireflection effect of F coating and the effect of F doping on a TiO₂ ETL, which increases the amount of light transmitted into the PSC due to the extremely low refractive index (≈1.39) and drastically improves the electrical properties of TiO₂. Consequently, the J_SC of the F coating and doping perovskite solar cell (F-PSC) increased from 25.05 to 26.01 mA cm⁻², and the power conversion efficiency increased from 24.17% to 25.30%. The unencapsulated F-PSC exhibits enhanced air stability after 900 h of exposure to ambient environment atmosphere (30% relative humidity, 25 °C under dark condition). The inclined F sputtering process in this study can become a universal method for PSCs from the development stage to commercialization in the future.