Kernel Composition Research Articles

Metabolic profile of fatty acids, phenolic compounds, and methylxanthines of cocoa kernels (Theobroma cacao L.) from different cultivars produced in cabruca and full sun farming systems

The demand for high-quality cocoa beans has increased in line with the growing global demand for chocolate. The chemical composition of cocoa beans can vary according to their origin and growing conditions. In this context, this study evaluated the influence of the cultivar type (CCN51 and PS1319) and the cocoa management system (cabruca and full sun) on the chemical composition of unfermented cocoa kernels. The cultivation system influenced the fatty acid composition of cocoa kernels, with higher values of linoleic acid associated with the full sun system, although higher total lipid contents were obtained in the cabruca system. The cultivar influenced the content of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), total unsaturated fatty acids (UFA) and the saturated/unsaturated ratio (S/U). Lower levels of total phenolic compounds, total anthocyanins and antioxidant properties were found in the full sun system, especially in the PS1319 cultivar. Higher levels of epicatechin and catechin were found in the cocoa kernel of the CCN51 cultivar. Theobromine and caffeine were not influenced by the treatments. Neither the PCA of total lipids and fatty acids, nor the PCA of antioxidant properties, phenolic compounds and methylxanthines indicated an isolated clustering between cultivar and cultivation system. The results showed that the factors under study influenced the chemical composition of the unfermented cocoa kernel. Furthermore, they indicated that the migration from traditional systems, such as cabruca, to full sun systems can reduce the total lipids and phenolic compounds content of the cocoa beans. When planning new plantations, the choice of genetic material should also be carefully considered to produce higher-quality cocoa butter and beans with a higher phenolic compound content.

Bioactive composition and medicinal properties of Walnut kernels

The purpose of this review is to evaluate the biological compounds present in walnut kernels and also to assess potential human health benefits. Walnuts are one of the most important tree nuts, belonging to the Juglandaceae family. They are cultivated worldwide, primarily in temperate regions. Throughout history, walnut kernels have been utilized to treat various disorders such as diarrhea, diabetes mellitus, thyroid issues, cancer, anorexia, and infectious diseases, in addition to their dietary benefits. Presently, advanced techniques like UHPLC-MS/MS, HPLC-DAD chromatography, and GC–MS are employed to identify key compounds in walnuts. These include phenolic compounds, phenolic acids, tannins and related compounds, flavonoids, phytosterols, fatty acids, triglycerides, tocopherols, vitamins, and carotenoids. The review also demonstrates that walnut kernels possess numerous medicinal properties, including antioxidants, cardiovascular effects, anti-cancer effects, antidiabetic effects, hepatoprotective effects, and antimicrobial effects. The current review also gives details on plant origin, distribution, classification, cultivation, and consumption as food. The review also described the recent medicinal plant profile, identification, and screening of the active ingredients of walnut's kernels. Researchers around the world are taking an interest in the clinical evaluation of walnut's active ingredients. The current review also gives details of the most recent conducted clinical studies. Mostly the reviews of walnuts are focused on walnut cultivars and/or specific types of compounds, although our current review is mostly focused on the active ingredients of walnut kernels and their specified biological role. In conclusion, different varieties of walnuts are abundant in significant bioactive compounds that possess important medicinal properties.

Deciphering the Genetic Basis of Kernel Composition in a Maize Association Panel.

The primary objective in contemporary maize breeding is to pursue high quality alongside high yield. Deciphering the genetic basis of natural variation in starch, protein, oil, and fiber contents is essential for manipulating kernel composition, thereby enhancing the kernel quality and meeting growing demands. Here, we identified 12 to 88 statistically significant loci associated with kernel composition traits through a genome-wide association study (GWAS) using a panel of 212 diverse inbred lines. A regional association study pinpointed numerous causal candidate genes at these loci. Coexpression and protein-protein interaction network analyses of candidate genes revealed several causal genes directly or indirectly involved in the metabolic processes related to kernel composition traits. Subsequent mutant experiment revealed that nonsense mutations in ZmTIFY12 affect starch, protein, and fiber content, whereas nonsense mutations in ZmTT12 affect starch, protein, and oil content. These findings provide valuable guidance for improving kernel quality in maize breeding efforts.

The Biosynthesis Pattern and Transcriptome Analysis of Sapindus saponaria Oil.

The Sapindus saponaria (soapberry) kernel is rich in oil that has antibacterial, anti-inflammatory, and antioxidant properties, promotes cell proliferation, cell migration, and stimulates skin wound-healing effects. S. saponaria oil has excellent lubricating properties and is a high-quality raw material for biodiesel and premium lubricants, showing great potential in industrial and medical applications. Metabolite and transcriptome analysis revealed patterns of oil accumulation and composition and differentially expressed genes (DEGs) during seed development. Morphological observations of soapberry fruits at different developmental stages were conducted, and the oil content and fatty acid composition of the kernels were determined. Transcriptome sequencing was performed on kernels at 70, 100, and 130 days after flowering (DAF). The oil content of soapberry kernels was lowest at 60 DAF (5%) and peaked at 130 DAF (31%). Following soapberry fruit-ripening, the primary fatty acids in the kernels were C18:1 (oleic acid) and C18:3 (linolenic acid), accounting for an average proportion of 62% and 18%, respectively. The average contents of unsaturated fatty acids and saturated fatty acids in the kernel were 86% and 14%, respectively. Through the dynamic changes in fatty acid composition and DEGs analysis of soapberry kernels, FATA, KCR1, ECR, FAD2 and FAD3 were identified as candidate genes contributing to a high proportion of C18:1 and C18:3, while DGAT3 emerged as a key candidate gene for TAG biosynthesis. The combined analysis of transcriptome and metabolism unveiled the molecular mechanism of oil accumulation, leading to the creation of a metabolic pathway pattern diagram for oil biosynthesis in S. saponaria kernels. The study of soapberry fruit development, kernel oil accumulation, and the molecular mechanism of oil biosynthesis holds great significance in increasing oil yield and improving oil quality.

The effect of date (Phoenix dactylifera L.) varieties on bioactive compounds, phenolic constituents, fatty acids and element contents of date seed and oils

AbstractIn this study, the oil amounts, bioactive components, fatty acid profiles and element quantities of the date kernels (Osailah, Rothanh Qassim, Rushudiah, Nabtat‐Ali, Sbakah) were determined. The oil quantities of the date seeds were altered to be between 3.50 (Osailah) and 5.55% (Nabtat‐Ali). The total phenolic quantities of the seeds were assigned to be between 330.83 (Rothanh Qassim) to 365.42 mg GAE/100 g (Osailah) while antioxidant activities of date seeds are assessed to be between 13.89 (Rothanh Qassim) and 38.74% (Nabtat‐Ali). The total flavonoid quantities of the date seeds were displayed to be between 4824.83 (Osailah) and 9133.17 mg/100 g (Sbakah). The (+)‐ Catechin and 1,2‐dihydroxy benzene quantities of the date seeds were established to be between 75.01 (Rothanh Qassim) and 186.02 mg/100 g (Sbakah) to 67.43 (Rothanh Qassim) and 199.89 mg/100 g (Sbakah), respectively. Oleic acid amounts of the seed oils were altered to be between 45.89 (Rothanh Qassim) and 52.55% (Nabtat‐Ali). K, P, S, Ca and Mg were the key minerals of the date seeds. Considering the bioactive components, polyphenol contents, fatty acid composition and mineral content of date kernels, it is thought that date kernel powders can be added to some foods as a food supplement.

Optimizing feature selection with gradient boosting machines in PLS regression for predicting moisture and protein in multi-country corn kernels via NIR spectroscopy

Differences in moisture and protein content impact both nutritional value and processing efficiency of corn kernels. Near-infrared (NIR) spectroscopy can be used to estimate kernel composition, but models trained on a few environments may underestimate error rates and bias. We assembled corn samples from diverse international environments and used NIR with chemometrics and partial least squares regression (PLSR) to determine moisture and protein. The potential of five feature selection methods to improve prediction accuracy was assessed by extracting sensitive wavelengths. Gradient boosting machines (GBMs), particularly CatBoost and LightGBM, were found to effectively select crucial wavelengths for moisture (1409, 1900, 1908, 1932, 1953, 2174 nm) and protein (887, 1212, 1705, 1891, 2097, 2456 nm). SHAP plots highlighted significant wavelength contributions to model prediction. These results illustrate GBMs' effectiveness in feature engineering for agricultural and food sector applications, including developing multi-country global calibration models for moisture and protein in corn kernels.

Evaluation of antioxidant, antimicrobial, and bioactive properties and peptide sequence composition of Malatya apricot kernels.

This study used four different apricot (Prunus armeniaca) kernels cultivated in Malatya during two consecutive years. The varieties were Hacihaliloglu, Hasanbey, Kabaasi, and Zerdali. The physicochemical properties of the kernels were determined, and the bioactive content of the kernels was evaluated using kernel hydrolysates prepared using trypsin. With regard to the physicochemical properties of the kernels, the dry matter ratio and protein content were the highest in the Hacihaliloglu variety; the ash ratio was the highest in the Kabaasi variety, and the free oil ratio was the highest in the Hasanbey variety. The bioactive compound content changed according to kernel variety. Angiotensin-converting enzyme inhibitors activity was found to be the highest in the Hacihaliloglu and Hasanbey varieties, which had the lowest amygdalin content, and Zerdali had the highest amygdalin content. The antioxidant and antimicrobial effects of the kernels varied, with Hasanbey and Kabaasi generally having the highest content in both analyses. Moreover, a concentration of 20 mg mL-1 of the hydrolysate was determined to have a destructive effect for the microorganisms used in this study. The storage protein of the kernels, except Hacihaliloglu, was found to be Prunin 1, with the longest matching protein chain in the kernels being R.QQQGGQLMANGLEETFCSLRLK.E. The results suggest that the peptide sequences identified in the kernels could have antihypertensive, antioxidative, and Dipeptidyl peptidase IV (DPP-IV)inhibitory effects. Consequently, apricot kernels show potential for use in the production of functional food products. Of the kernels evaluated in this study, Hacihaliloglu and Hasanbey were deemed the most suitable varieties due to their higher bioactive content and lower amygdalin content. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Change Point Detection for Automatic Time Series Forecasting

Time series analysis, the process of learning patterns in time series data and making future predictions, is a challenging machine learning endeavor: the intricate and error-prone process of manual data fitting limits efficiency and scalability to larger datasets. Our research builds upon structure discovery research, paving the way for more effective short-term forecasting. We combine the adaptability of automatic change point detection with a fixed kernel composition, achieving accuracy comparable to traditional manual methods while reducing analysis time. This hybrid approach offers the best of both worlds: leveraging human expertise for precise fitting and capturing specific trends while utilizing an automated technique to recognize shifts and model complex relationships within the data dynamically. By demonstrating the effectiveness of automatic change point detection in conjunction with kernel composition, we work to develop time series usage in data analysis.

Enhancement of plasma assisted ignition by multi-voltage pulse discharges: A theoretical study

Currently, compression ignition engine technology is becoming less competitive compared to spark ignition engine technology due to emission standards. Lean combustion strategies are preferable for spark ignition engines, but they require enhanced ignition strategies compared to current stoichiometric spark ignition engines. In this paper, we lay physical foundations for such enhanced ignition strategies that can support lean combustion strategies in spark ignition engines. In this theoretical study, we conduct a preliminary foray into the possibility of controlling the species composition of a cold-plasma kernel as a precursor for an ignition process. We consider a multi-pulse electric source system coupled to a DBD (Dielectric Barrier Discharge) electrode immersed in a dry air medium. The coupled system is designed such that the medium in the electrodes’ gap is subjected to a pulse structure which is composed of a peak voltage followed by a secondary low-voltage pulse. Use is made of a comprehensive mathematical model that includes the electric field, potential and current, with the relevant conservation equations for 24 species and 168 kinetic reactions, while considering different energy modes (rotational, vibrational, electronic excitation, dissociation, and ionization) within the electrodes’ gap. The model was validated against independent published results, and was used to understand the mechanism of energy conversion to species that play a central role in terms of the ultimate ignition dynamics. Various pulse repetition frequencies and different pulse constructions were considered. Special attention was given to the amount of deposited energy, and to the energy channeled to known ignition supportive modes and species. The present results show that the energy deposition can be divided into two main stages which are characterized by high and low voltage levels, respectively. We propose that for more successful ignition, the amount of energy deposition during the second (low voltage) stage should be higher than that during the first (high voltage) stage. During the second stage, the deposition of energy into specific modes can be fine-tuned by setting appropriate voltage levels. Based on these findings, we demonstrate how control of the sequence of voltage pulses can further increase enhancement of ignition and combustion promoting processes.

Influence of Chemical Composition and Degree of Fragmentation of Millet Grain on Confused Flour Beetle (Tribolium confusum Duv.) Infestation

Owing to its wealth of nutritional values and low cultivation requirements, millet can become a key crop in global food systems. Thus, the Food and Agriculture Organization (FAO) declared that 2023 is the International Year of Millet. The introduction of this cereal and its products into universal food circulation calls for a multidimensional approach, which would also consider threats posed by pests during the storage of cereal kernels. The aim of this study was to evaluate the development of the confused flour beetle (Tribolium confusum Duv.) on common millet (Panicum miliaceum L.) and products obtained from this cereal, and to analyze the factors which influence its development (chemical composition of kernels, degree of their fragmentation). The study was conducted under laboratory conditions in an environmental test chamber (temperature 30 °C, humidity 70%, light—complete darkness). Millet grains of the Jagna cultivar and its products were weighed at 20 g, placed in vinidur dishes, and 10 beetles were then placed on the prepared material. The experiment demonstrated that the millet grain and food products obtained from this grain (millet flour, flakes, groats) could be a suitable habitat for the development of the confused flour beetle. The key regulator for the development of this pest insect is the degree of fragmentation of the infested material. The millet grain and millet products (except millet flour) are characterized by less numerous developments of beetle progeny than wheat products, which could be another advantage of millet in an integrated international system of grain storage. Chemical analysis also showed a significant correlation between the abundance of offspring generation and the content of crude fat (especially linoleic acid—C 18:2). Knowledge of the resistance or susceptibility of millet to storage pests may be useful in implementing integrated principles of protection of stored products against pests.

Chemical differences between brown centre and white macadamia kernels

Nuts are susceptible to many quality issues, including discoloration defects in kernels. These discolouration defects can affect their market value and result in significant economic losses to both growers and processors. In macadamia, this quality issue is called brown centres and has been related to storage at high temperatures and moisture concentrations. However, the chemical differences between brown centre and white macadamia kernels have not previously been studied. We aimed to determine the chemical differences between macadamia kernels with brown centre defects and kernels that were white and cream coloured. We used brown and white kernel samples from 20 commercially processed batches of macadamia. From each batch, we selected brown centre samples and compared their chemistry with white kernel samples from the same batch. We compared the moisture concentration, sugar concentration, nutrient concentration, fatty acid profile and peroxide value of brown centre defect and white kernel samples. Our results showed that brown centres had a higher moisture concentration compared with white kernel samples (5.16 % vs 2.91 %, respectively, P < 0.05). Reducing sugars of fructose (0.61 %) and glucose (0.53 %) concentrations were only detected in brown centre, although the sucrose concentration was not significantly different. Most nutrient concentrations were higher in brown centres compared with white kernels. Nitrogen concentration was significantly higher in brown centre than white centres (2.10 % vs 1.82 %, respectively, P < 0.05). Calcium concentration was also higher in brown centre than white macadamia kernels (608.44 mg/kg vs 419 mg/kg, respectively, P < 0.05). Our study suggests that high moisture concentrations in macadamia kernels could have triggered the hydrolysis of sucrose into reducing sugars (fructose and glucose). In addition, reducing sugars and proteins can react in the Maillard reaction to form brown colouration in nuts. This is the first study to comprehensively compare the nutritional composition of brown centres and white macadamia kernels. We recommend appropriate drying and storing of macadamia nuts to prevent sucrose degradation into reducing sugars and decrease the formation of brown centres through the Maillard reaction.

Foliar nutrition improves kernel composition and quality in hazelnut

Foliar nutrition improves kernel composition and quality in hazelnut

Defining durum wheat ideotypes adapted to Mediterranean environments through remote sensing traits.

An acceleration of the genetic advances of durum wheat, as a major crop for the Mediterranean region, is required, but phenotyping still represents a bottleneck for breeding. This study aims to define durum wheat ideotypes under Mediterranean conditions by selecting the most suitable phenotypic remote sensing traits among different ones informing on characteristics related with leaf pigments/photosynthetic status, crop water status, and crop growth/green biomass. A set of 24 post-green revolution durum wheat cultivars were assessed in a wide set of 19 environments, accounted as the specific combinations of a range of latitudes in Spain, under different management conditions (water regimes and planting dates), through 3 consecutive years. Thus, red-green-blue and multispectral derived vegetation indices and canopy temperature were evaluated at anthesis and grain filling. The potential of the assessed remote sensing parameters alone and all combined as grain yield (GY) predictors was evaluated through random forest regression models performed for each environment and phenological stage. Biomass and plot greenness indicators consistently proved to be reliable GY predictors in all of the environments tested for both phenological stages. For the lowest-yielding environment, the contribution of water status measurements was higher during anthesis, whereas, for the highest-yielding environments, better predictions were reported during grain filling. Remote sensing traits measured during the grain filling and informing on pigment content and photosynthetic capacity were highlighted under the environments with warmer conditions, as the late-planting treatments. Overall, canopy greenness indicators were reported as the highest correlated traits for most of the environments and regardless of the phenological moment assessed. The addition of carbon isotope composition of mature kernels was attempted to increase the accuracies, but only a few were slightly benefited, as differences in water status among cultivars were already accounted by the measurement of canopy temperature.

Impact of low temperature on the chemical profile of sweet corn kernels during post-harvest storage

Fresh sweet corn has a limited shelf-life due to its high moisture and high sugar content. Low temperature storage is an effective technique employed to extend the shelf-life. However, changes in the chemical composition of sweet corn kernels at low temperatures are not fully understood. In this study, kernels stored at low temperature exhibited higher levels of soluble sugars and lower starch content. In total, 1365 metabolites were characterized in sweet corn kernels. 593 and 308 differentially accumulated metabolites (DAMs) were identified in sweet corn kernels stored at normal and low temperature, respectively. 607 DAMs were identified at low temperature compare to normal temperature. DAMs were consistently enriched in flavonoid biosynthesis, linoleic acid metabolism and sphingolipid metabolism. Moreover, dozens of metabolites were identified as potential biomarkers for post-harvest storage effects in sweet corn. These results extend our knowledge of the dynamic changes in sweet corn kernels stored at low temperatures.

Effect of γ-irradiation on the physicochemical and sensory properties of fresh walnut kernels (Juglans regia) during storage

The current study examined the total phenol content, antioxidant activity, sensory quality and fatty acid composition of fresh walnut kernels as a function of irradiation dose to determine dose levels that resulted in the least amount of undesirable changes to fresh walnut kernels at regular intervals of time. Fresh walnut kernels were exposed to 60Co radiation at doses of 0.5, 1.5, 3, 6, 8, and 10 kGy and stored at ± 4 °C for 28 days. Irradiation doses of 0.5 and 0.1 KGry have no significant effect on total phenol content (1.56±0.04–1.30±0.02mgGAE/g), antioxidant activity (95±0.02–85±0.01%), peroxide value (0.49±0.04–0.72±0.03%) and free fatty acid values (0.14±0.01–0.29±0.03%) respectively. However, irradiation doses of 1.0, 2.0, 3.0 and 4.0 resulted in increased peroxide values (0.89±0.02%, 0.98±0.01%, 1.05±0.01%, 1.17±0.03%), increased free fatty acid values(0.05±0.01%, 0.58±0.03%, 0.63±0.02±0.01%, 0.67±0.04%) and also the organoleptic quality were decreased (2.0 ± 0.01, 1.7 ± 0.03, 1.4 ± 0.02%, 1.2 ± 0.03%) during 28 days of storage. The use of gamma irradiation appears to be a promising technology for improving the chemical quality of fresh walnut kernels, but food safety concerns must be addressed before it can be recommended as a useful conservation alternative.

Influence of sustained deficit irrigation and foliar kaolin application on almond kernel composition

Deficit irrigation and kaolin foliar application are agronomic practices that have been demonstrated to improve productivity and physiological response in almond trees but there is no consistent information on the effects on the kernel composition. The objective of this study was to evaluate the effect of different Sustainable Deficit Irrigation (SDI) strategies and kaolin application on some physicochemical composition of the cv Ferragnès almond (Prunus dulcis (Mill.) D.A. Webb). A randomized block design with five treatments was developed: non-irrigation (NI), non-irrigation with foliar kaolin application (NI+K), full irrigation (FI), and two levels of SDI receiving 70% and 35% of evapotranspiration (SDI75 and SDI35). Pomological parameters, volatile profile and oil composition were analyzed. SDI effect on kernel weight was reduced against full irrigation (FI) but substantially improved in comparison with the rainfed treatments (NI and NI+K). Irrigation treatments showed a lower volatile compounds concentration in comparison with rainfed treatment. The fatty acid composition of the oil was significantly affected, with all the irrigated treatments having higher oleic acid contents than the rainfed treatments, and therefore an expected increased shelf life. Kaolin application had no positive effects on the non-irrigated trees, other than an apparent increase in the total volatiles, a tendency also observed in the NI. Moderate water stress levels (SDI35) improved the synthesis of tocopherols compared to NI, FI and SDI70, which could be related to the adaptation of the almond tree to drought. SDI35 is therefore regarded as a very interesting approach, with significant improvements in comparison with non-irrigated trees, and a clear saving on water against full irrigation without significant pomological and chemical alterations.

Foliar Nutrition Influences Yield, Nut Quality and Kernel Composition in Hazelnut cv Mortarella.

In hazelnut, foliar nutrition is utilized globally to integrate microelement deficiencies and optimize their assimilation and effects on yield performances. Nevertheless, nut quality and kernel composition can be positively affected by foliar nutrition. Recently, several studies pointed out the need for increasing the sustainability of orchard nutrition by proposing the management of not only micronutrients, but also main components, such as nitrogen, through foliar spraying. In our study, different foliar fertilizers were used to understand the effectiveness of supporting hazelnut productivity and nut and kernel quality. Water was used as a control. Foliar fertilizations affected tree annual vegetative growth, improved kernel weight and decreased the incidence of blanks compared to the control. Differences in fat, protein, and carbohydrate concentration were also found among treatments, with increased fat concentrations and total polyphenols content in fertilized treatments. Foliar fertilization improved the oil composition of the kernels, though fatty acid composition responded differently to nutrients spray. Oleic acid concentration was promoted, while palmitic acid concentration was reduced in fertilized plants compared to control trees. Furthermore, CD and B trees were characterized by an increase in the ratio of unsaturated/saturated fatty acids compared to untreated trees. Finally, foliar spraying improved lipid stability compared to the control due to higher total polyphenol concentration.

Chemical composition of copra, palm kernel, and cashew co-products from South-East Asia and almond hulls from Australia.

Oilseeds and nut co-products can be used as alternative feed ingredients in animal diets because they may have a lower cost than traditional ingredients. A study was, therefore, conducted to determine the chemical composition of copra, palm kernel, and nut coproducts from South-East Asia or Australia. The hypothesis that country of production influences nutritional composition was tested. Oilseed meals included 2 copra expellers, 3 copra meals, and 12 palm kernel expellers. One source of almond hulls and cashew nut meal were also used. Samples were obtained from suppliers located in South-East Asia or Australia. All samples were analyzed for dry matter, gross energy, nitrogen, amino acids (AA), acid-hydrolyzed ether extract (AEE), ash, minerals, insoluble dietary fiber, and soluble dietary fiber. Copra and nut coproducts were also analyzed for total starch and sugars. Copra expellers had greater (p<0.05) concentrations of dry matter and AEE compared with copra meal. However, copra meal had greater (p<0.05) concentrations of total dietary fiber (soluble and insoluble) and copper than copra expellers. Palm kernel expellers from Indonesia had greater (p<0.05) concentration of histidine and tyrosine compared with palm kernel expellers from Vietnam. Almond hulls was high in dietary fiber, but also contained free glucose and fructose, whereas cashew nut meal was high in AEE, but low in all free sugars. Copra expellers have greater concentration of AEE, but less concentration of total dietary fiber when compared with copra meal, and except for a few AA, no differences in nutrient composition of palm kernel expellers produced in Indonesia or Vietnam were detected. According to the chemical composition of nut co-products, cashew nut meal may be more suitable for non-ruminant diets than almond hulls.

Influence of Integrated use of Organic and Inorganic sources of nutrients on quality parameters of Sweet Corn

A field experiment entitled “Sustaining soil health and productivity of sweet corn through nutrient management” was conducted at Agricultural College Farm, Bapatla using sweet corn hybrid maize Mahy-301 as a test crop. The experiment comprising of 10 treatments was laid out in completely randomized block design and were replicated thrice. The biochemical composition of sweet corn kernel was significantly influenced by the different nutrient management practices. The maximum protein content (10.56%) was observed in T2 (100 per cent RDF) whereas the highest starch content (54.33 %) and sucrose content (8.57 %) was observed in treatment which received 50 per cent RDF with FYM @ 5 t ha-1

Parameterization of kernels of the Volterra series for systems given by nonlinear differential equations

The presented article is devoted on an issue regarding to the transformation of nonlinear models of a certain class to the Volterra functional series. The new identification method based on analytical input and output of a system was developed. The key task of representing kernels was achieved by Frechet functional derivative. Explicit calculation of the functional derivative for the output was solved using mean-value theorem, while the sifting property of the Dirac function was used in order to solve derivative of input. Attention is given to the calculation of the second-order functional derivative. The procedure for adding linear kernels to the composition of a quadratic kernel is described. All techniques of the method to other components of the model are described in detail. The method's outcome is differential equation, which allows representation of kernels. An illustrative example of the transformation of the nonlinear differential Riccati equation is considered. The form of a subsystem consisting of linear and quadratic kernels for adding to a complex system is shown. Linear and quadratic kernels were parameterized using operational calculus within the example. The agreement of the obtained analytical results, with the frequency characteristics, which was obtained by the test signals method, is shown.