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Drying is a crucial and energy-consuming process in black tea manufacturing that is aimed at reducing moisture content and terminating enzymatic reactions in tea leaves. In Sri Lanka, an endless chain pressure (ECP) dryer is commonly used for drying, but it consumes a significant amount of energy, necessitating the optimization of drying conditions. The current drying temperature at the Houpe tea factory in Ratnapura, Sri Lanka is 121 °C (250 °F), and it has not been optimized for a considerable period. As a result, energy consumption and wastage are high, leading to an inferior quality of black tea. To optimize factory conditions, tea leaves were dried under different temperatures: 115 (T1), 118 (T2), 121 (T3), 124 (T4), and 127 (T5) °C. Energy consumption, energy wastage, and specific energy consumption (SEC) for tea drying were calculated. Additionally, chemical and sensory analyses of samples of made tea were performed. SEC and energy wastage were significantly (p < 0.05) lower for treatments T1 and T2 than for other treatments. The theaflavin and thearubigin contents were significantly (p < 0.05) higher while total phenolic content was moderate for treatment T2. The sensory parameters of T2 outperformed other treatments. Based on these results, the optimum drying temperature for the ECP dryer was determined to be 118 °C and this temperature has been recommended for this factory. [ABSTRACT FROM AUTHOR]

Nano-nitrogen fertilizers (NNFs) have emerged as a promising technology in the field of agriculture, offering potential solutions to improve nutrient uptake efficiency, enhance crop productivity, and reduce environmental impacts. NNFs showed superior characteristics and performance on crops and, therefore, became a potential alternative to conventional nitrogen (N) fertilizers. These fertilizers enhance plant uptake while simultaneously reducing environmental losses. For example, a hydroxy appetite-based urea NNF extended the N release for 112 days, which could cover the N demand of many perennial crops, thus reducing losses. The reported NNFs in this review increased the yield by 10–80% compared to conventional fertilizers. Additionally, their small particle size increases crop acclimation and decreases the application rate. With all these beneficial traits of NNFs, they potentially contribute to achieving Sustainable Development Goals (SDGs). This review article summarizes the materials used in NNF formulation, methods of preparing NNFs, and their crop responses. Also, it highlights the limitations identified in the research studies and provides research recommendations for the future. Further, it provides a critical assessment of the current state of NNFs and their prospects for revolutionizing modern agriculture to attain SDGs. [ABSTRACT FROM AUTHOR]

The leaf extracts of Gymnema sylvestre consist of secondary metabolites which are well known for antioxidant activity. This study aimed to measure the drying characteristics of G. sylvestre leaves under far-infrared radiation (FIR) and to optimize the specific energy consumption for drying and antioxidant activity of ethanol-water extract of dried leaves. Fresh leaves were harvested and exposed to combinations of four different temperatures (125, 150, 175 and 200 °C) and exposure times (5, 10, 15 and 20 min). Drying kinetics, energy consumption, color changes, total phenolic content (TPC) and antioxidant activities were quantified. Both temperature and drying time have significant (p < 0.05) effects on drying characteristics and antioxidant activity. The equilibrium moisture content was achieved at 200 °C and 18 min. The specific energy decreased and total color changes increased with temperature. Under lower temperatures (125 and 150 °C), TPC and antioxidant activity increased with exposure time, whereas higher exposure time (20 min) with high temperatures (175 and 200 °C) significantly decreased TPC and antioxidant activity. The highest TPC of 30.5 mg TAE/g leaf-fresh weight was achieved at 200 °C and 15 min. The optimal drying conditions achieved from the dissimilarity function method were 200 °C and 8.4 min. [ABSTRACT FROM AUTHOR]

The effect of newly developed controlled-release fertilisers (CRFs); Epox5 and Ver-1 and two levels of Fe2+ applications (478 and 239 kg-FeSO4 ha−1) on controlling nitrogen (N) losses, were tested on ryegrass, in a climate-controlled lysimeter system. The Epox5 and Ver-1 effectively decreased the total N losses by 37 and 47%, respectively, compared to urea. Nitrous oxide (N2O) emissions by Ver-1 were comparable to urea. However, Epox5 showed significantly higher (p < 0.05) N2O emissions (0.5 kg-N ha−1), compared to other treatments, possibly due to the lock-off nitrogen in Epox5. The application of Fe2+ did not show a significant effect in controlling the N leaching loss and N2O emission. Therefore, a dissimilatory nitrate reduction and chemodenitrification pathways were not pronounced in this study. The total dry matter yield, N accumulation, N use efficiency and soil residual N were not significantly different among any N treatments. Nevertheless, the N accumulation of CRFs was lower in the first month, possibly due to the slow release of urea. The total root biomass was significantly (p < 0.05) lower for Epox5 (35%), compared to urea. The hierarchical clustering of all treatments revealed that Ver-1 outperformed other treatments, followed by Epox5. Further studies are merited to identify the potential of Fe2+ as a controlling agent for N losses. [ABSTRACT FROM AUTHOR]