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In Vietnam, the cultivation and production of coffee have been expanding over the past few decades and are known as an important part of the national economy. However, the scientific data regarding the internal compositions of coffee have still been limited, especially the changes during the processing, typically the roasting period. The present study aimed to demonstrate an insight into the variations in chlorogenic acid, caffeine, total phenolic contents (TPCs), and trolox equivalent antioxidant capacities for two common coffee species, that is, Robusta and Arabica, and three roasting levels, that is, light, medium, and dark. Generally, Robusta coffee performed higher chlorogenic acid, caffeine, and TPCs, resulting in dominant antioxidant capacities compared to Arabica. High Pearson correlation coefficients (calculated by SPSS) were found for most pairs of parameters, r > 0.80. Regarding roasting levels, a descending order was highlighted for most analytical parameters: light > medium > dark. Two parallel processes in the roasting period were revealed by observing the antioxidant capacities, that is, thermal degradation and formation of other antioxidants by the Maillard reaction. Principal component analysis (SIMCA-P 11) was attempted to discriminate the available coffee samples by their species and roasting levels, indicating proper classification (the cumulative variance is 95.3%). [ABSTRACT FROM AUTHOR]

A smartphone-based colorimetric detection method was optimized for measuring the fluoride content in tea extracts using zirconium-xylenol orange reagent. The images of the formed color complex in the presence of fluoride were captured and analyzed their color components through the RGB (Red, Green, Blue) vector values. To maintain the capturing conditions, a colorimetric box (150 × 70 × 90 mm) was self-designed by optimizing the smartphone camera-sample holder/cuvette distance and inside brightness. The calibration curve was constructed from 0.5 to 25 mg/L with the goodness of linearity (R2 > 0.995). Favorable repeatability and reproducibility were obtained (RSDr = 5.01% and RSDR = 5.02%), according to the Appendix F of AOAC (2016). UV–Vis and F ion-selective electrode were simultaneously conducted as reference methods for the developed smartphone-based method, demonstrating comparable fluoride content results in tea extracts obtained from these methods. Using 2.5 g tea brewed in 100 mL of deionized water at 90 °C for 60 min, a descending fluoride content order was achieved: black tea (3.31–3.85 mg/L) > oolong tea (2.38–2.65 mg/L) > green tea (2.25–2.97 mg/L) > white tea (2.28–2.31 mg/L). The smartphone-based method was also applied to evaluate the effects of different brewing conditions on the fluoride content in tea extracts, indicating the higher brewing temperature and prolonged time could accelerate the release of fluoride in tea extracts. This study provides a quality control tool for tea consumers and manufacturers as well as contributes to enrich the applications of smartphone-based methods in the food sections, especially for Vietnam with the diversity of agricultural products. [ABSTRACT FROM AUTHOR]

• A home-made colorimetric analysis box equipped with a smartphone was designed. • Advantages of simplicity, portability, reduced-volume, and low cost are obtained. • No statistical differences were observed between the proposed and UV–vis methods. • TPCs in tea liquors are proportional to the rising brewing temperature and time. • The proposed methods can be applied for other criteria and used by tea manufacturers. The total phenolic contents (TPCs) represent the bioactive substances and antioxidant capacities of flora products. The present study employed digital images from a smartphone to determine the TPCs in tea products and their liquors. Various parameters related to the portable home-made colorimetric analysis box design were optimized to achieve the most favorable capturing condition. The proposed method performance was evaluated, which agreed with the Appendix F of AOAC (2016). In comparison with the standard UV–vis, no statistical differences (t-tests, P = 95 %) were observed, and there were advantages of simplicity, portability, sample volume reduction, decreased analysis time, low-cost operation, especially the potential to be used by tea producers, managers, and consumers to quickly analyze the TPCs. The results demonstrate the descending TPCs orders of green > white > oolong > black teas (recoveries of 95–98 %) and the increase of TPCs in tea liquors regarding the rising brewing temperature and duration. [ABSTRACT FROM AUTHOR]

Vietnam has diverse and long-established tea plantations but scientific data on the characteristics of Vietnamese teas are still limited. Chemical and biological properties including total polyphenol and flavonoid contents (TPCs and TFCs), antioxidant activities (DPPH, ABTS, FRAP, and CUPRAC), as well as the contents of caffeine, gallic acid, and major catechins, were evaluated for 28 Vietnamese teas from North and South Vietnam. Higher values of TPCs and TFCs were found for green (non-oxidised) and raw Pu'erh (low-oxidised) teas from wild/ancient tea trees in North Vietnam and green teas from cultivated trees in South Vietnam, as compared to oolong teas (partly oxidised) from South Vietnam and black teas (fully oxidised) from North Vietnam. The caffeine, gallic acid, and major catechin contents depended on the processing, geographical origin, and the tea variety. Several good Pearson's correlations were found (r2 > 0.9) between TPCs, TFCs, the four antioxidant capacities, and the content of major catechins such as (–)-epicatechin-3-gallate and (–)-epigallocatechin-3-gallate. Results from principal component analysis showed good discriminations with cumulative variances of the first two principal components varying from 85.3% to 93.7% among non-/low-oxidised and partly/fully oxidised teas, and with respect to the tea origin. [ABSTRACT FROM AUTHOR]

This paper aims to describe a trend in coverage of maternal care services, and provides a detailed analysis of socio-economic correlations to the existing inequities. The paper uses data from the Vietnam Multiple Indicator Cluster Survey 2000, 2006, 2011, and 2014. In the MICS, there were 9,117 women in 2000, 9,473 women in 2006, 11,614 women in 2011, and 9,827 women in 2014 participated in. We found the coverage of antenatal care increase from 68.6% in 2000 to 95.9% in 2014. Similarly, the percentages of women who gave birth with the assistance of skilled staff increased during the studied period ( from 69.9% in 2000, 87.7% to 94.5% in 2014). However, improvements in antenatal care and skilled birth attendance in Vietnam have been uneven across different segments of the population. In all the four surveys, the proportions of women who received ANC by a skilled staff and percentages of women who gave birth with the assistance of a skilled health personnel were much higher among those with higher education, belonged to Kinh majority tribe, had better economic status, and lived in an urban area. The degrees of inequity in both antenatal and delivery care in Vietnam are likely to increase over time. [ABSTRACT FROM AUTHOR]