Analysing the performance of the NARX model for forecasting the water level in the Chikugo River estuary, Japan.

Estuaries are dynamic environments which are driven by various natural processes like river discharge, tides, waves, influx of saline water and sediments, etc. These ecosystems are the most sensitive to sea level rise and fluctuations in river discharge associated with climate change. A direct response of sea level rise and river discharge can be observed in the water level of estuaries. However, existing models have not considered these parameters for forecasting water level. This paper focuses on developing a water level forecast model for the Chikugo River estuary in Japan using Nonlinear Autoregressive with Exogenous inputs (NARX Model). NARX neural network was used to do the one-step-ahead prediction of water level considering the various parameters that can very well be influenced by climate change: previous water level, river discharge, and salinity. Accordingly, three models were developed: (i) Model I considering previous water level; (ii) Model II additionally considering river discharge; and (iii) Model III additionally considering salinity. All the models showed appreciable performance in forecasting the water level. Model III had the best correlation with the water level with a cross-correlation value of 0.6030, while the river discharge had only a cross-correlation of 0.1113 indicating that the Chikugo River estuary is tide-dominated. The model was trained using different combinations of available data - previous water level, river discharge, and salinity. Cross-correlation results showed a better correlation between water level and salinity than various other combinations trained. Therefore, tidal intrusion influences the water level in the estuary, thereby depicting that sea level rise can affect the water level, and its influence can be well predicted by the developed model. The water level significantly affects the flora and fauna and the predictability of future estuarine floods can help in taking necessary mitigation strategies.

Influence of chemical modifications on dynamic rheological behaviour, thermal techno-functionalities, morpho-structural characteristics and prebiotic activity of banana starches.

Banana starch is explored for its use in food and pharmaceutical applications. In this study, in order to improve the techno-functional properties of native banana starch (NS), different chemical modifications namely acid thinning (AT), oxidation (OX), sodium-trimetaphosphate method (STMP), cross linking phosphorylation (CLP), hydroxypropylation (HYP) were employed. Among the modified starches, amylose content was higher in CLP starch and the least was observed in AT. Resistant starch (RS) of HYP (65.38 %) and CLP starches (62.76 %) were significantly higher than other modified starches. Lesser amylose, higher water solubility and lower swelling of AT starch resulted in inferior paste clarity and inability to make a firm gel. Non-Newtonian behaviour of starch gels were observed from static viscosity observations. The dynamic rheological behaviour of the starch gels affirmed the higher gel strength of STMP (0.46) and CLP (0.56) starches. Imperfection and exo-corrosion in starch morphology was observed through SEM and influence of chemicals on the starch structure was elucidated through FTIR and XRD analyses. Except AT starch, modified starches with higher RS resulted in lowering glycemic index (57-69 %). STMP starches recorded highest prebiotic activity score of 0.88. Chemical modifications enable to enhance the functionalities of banana starch and offers potential industrial uses.

Influence of food hydrocolloids on the structural, textural and chemical characteristics of low-fat banana chips.

Banana chips are gaining popularity as a deep-fried product for its unique taste and flavour. This study is aimed to investigate the effect of hydrocolloids on oil absorption, physico-chemical and sensory properties of banana chips from two different varieties (var. Popoulu and var. Nendran), when fried at 180 °C for 3 min. The reduction in oil content was about 15%-35% and 19%-30% for hydrocolloid treated Popoulu and Nendran chips, respectively. The Free fatty acid content (FFA) of hydrocolloid treated banana chips was lower than that of untreated chips. The peroxide value (PV) values of all samples fell below 2 meq oxygen kg-1. CMC pre-treated banana chips were crispier than other formulations on both the varieties. Microscopic analysis showed the improved cellular integrity without large void spaces in hydrocolloid treated banana chips. PCA analyses elucidated that variables such as physical appearance, colour, crispiness, after taste, overall acceptability contributed positively, whereas hardness and sogginess contributed negatively to the correlation among the variables. From the chemical and sensory attributes, 0.5% CMC treated Popoulu chips and 1% CMC treated Nendran chips is recommended to produce chips with lower oil content.

Exploring differences in the physicochemical, functional, structural, and pasting properties of banana starches from dessert, cooking, and plantain cultivars (Musa spp.).

Banana starch, with its nutritional and functional properties, opens up new opportunities for the food industry, which is seeking new starch sources to fulfil rising demand. Herein, physico-chemical, and functional properties of banana starches isolated from dessert, plantain, and cooking cultivars were investigated. Starch yield was higher in Popoulu (30.58%) and Monthan (27.82%). Starch granules registered irregular forms with granule sizes ranging from 8.9 to 55.09 µm. Among the cultivars, the amylose content was ranged between 25.05 and 31.86%. Total starch (95.86 and 95.60%,) and resistant starch (65.56 and 59.20%) were higher in Saba and Monthan respectively. Flour colour index (86.2-90.6) was higher in banana starches. Differential scanning calorimetry and rapid viscosity studies confirmed that starches from Saba (87.67 and 85.71 °C) Monthan (85.36 and 81.65 °C) have a higher gelatinization property. Banana starches were B and C-type with varying crystallinity levels (21.19-52.01%). The in-vitro starch digestibility revealed that Saba starch has a lower hydrolysis rate with lesser glycemic index. PCA showed the greater impact of amylose and resistant starch content on the grouping of varieties. These findings would be useful for food and non-food industries in terms of using banana starch in various food compositions and other industrial applications.