The influence of selected cultivation on the content of total protein and amino acids in the potato tubers

Abstract

The aim of study was to determine the effect of selected cultivation operations, such as nitrogenous fertilization (60, 90 kg N/ha), row spacing (62, 82, 102 cm), compaction of soil with wheels of farm aggregates (the numbers of passing 2×, 5×, 8×), on quality changes of two potato varieties (Irga and Ekra). The total protein content in the tubers of the tested potato varieties increased with the increase of the nitrogenous fertilization (90 kg N/ha). Genotype features of the tested potato tubers define the amino acid limiting the protein biological value (CS) to be leucine in Irga variety and isoleucine in Ekra variety. It is also genotype that influences the second limiting amino acid. It is the sum of sulphuric amino acids (Cys + Met) in respect to Irga variety and valine in respect to Ekra variety. The dose of 90 kg N/ha decreases the protein biological value (EAAI) of the tubers of Ekra variety, which is high in starch.Keywords: potato; tuber; total protein; biological value of protein; amino acids; nitrogen fertilization; row spacing; soil compaction Protein content in tubers is an important element of the evaluation of potato quality. Although when compared to other crop plants, potatoes contain a small amount of protein (2.0-2.5% f.m.), they are an important element of human and animal diet, due to high biological value of protein -very good amino acid composition (Ciećko et al. 1999). Potato protein is plant protein of high value for both humans and animals. Potato varieties are characterised by differentiated, genetically conditioned predisposition to protein accumulation in tubers. However, similarly to most quality characteristics, protein content can be modified by various factors, such as environment, soil and tillage (Mazurczyk and Lis 1999). The basic protein components are amino acids, which, similarly to nucleic acids, take part in all intracellular processes in living organisms. The amino acid composition of proteins is important from the nutrition point of view. The amino acid composition determination acids (exogenous), namely tryptophan, phenylalanine, lysine, treonine, methionine, leucine and valine, are valuable. These amino acids are necessary for all types of the examined animals. However, a rigid set of amino acids necessary for all animals cannot be applied because some of them may require specifically a certain type of an amino acid. The analysis of the amino acid composition of the potato protein makes it possible to classify the protein as full-value, as it contains a high amount of the essential amino acids, particularly lysine (Wieczer and Gonczarik 1977). MATERIAL AND METHODSThe experimental material consisted of the tubers of two varieties: edible Irga and industrial Ekra. A field experiment was carried out in the vegetation seasons of 1997-1999 at the Experimental Farm Station, Zawady and on the experimental field of the Department of Soil Cultivation and Plant Growing, Plant Production Institute of the University of Podlasie in Siedlce. The experiment was planned in...

Economic Optimum Nitrogen Fertilization Rates and Nitrogen Fertilization Rate Effects on Tuber Characteristics of Potato Cultivars

“…For all cultivars, total protein concentration in the potato tubers increased with increasing N fertilization rates (Table 5). Mitrus et al (2003) also found an increase in the total protein concentration in the potato tubers with the increase in N fertilization. The protein concentration is an important trait for potato quality.…”

“…However, potato is important in the human diet, due to the high biological value of the protein and its amino acid composition. Similarly to most quality characteristics, protein concentration can be modified by various factors, such as environment, soil, tillage (Mitrus et al 2003), N fertilizer, and cultivar. For Ágata, Asterix, Atlantic, and Monalisa, tuber pH was not affected by N fertilization rate; average values were 5.51, 5.58, 5.61, and 5.56, respectively.…”

Carboidratos e matéria seca de tubérculos de cultivares de batata influenciados por doses de nitrogênio

“…Informações sobre a influência de fertilizantes, especificamente do N, sobre a qualidade de tubérculos de batata tem sido obtidas (Mitrus et al, 2003;Goffart et al, 2008), mas os resultados são variáveis, pois a interações entre dose de N, genótipo e condições de crescimento da planta são complexas. Dependendo do ano, dose de N acima da recomendada aumentou o teor de açúcares nos tubérculos de batata (Long et al, 2004) e diminuiu o teor de amido dos tubérculos (Westermann et al, 1994).…”

The influence of herbicides and their mixtures on total proteins content and on proper proteins in potato tubers

“…Once more, each cultivar reacted by increasing the protein content after chemical interventions. The significance of the influence of cultivars on the given characteristic was proved by numerous researches (Roztropowicz 1989, Mazurczyk 1994, Mitrus et al 2003.…”

“…Once more, each cultivar reacted by increasing the protein content after chemical interventions. The significance of the influence of cultivars on the given characteristic was proved by numerous researches (Roztropowicz 1989, Mazurczyk 1994, Mitrus et al 2003.Weather conditions during the experimental years significantly differentiated the total protein content. The tubers of the mild drought year 2001 gathered the highest content of the given component but a lot less during the humid seasons of vegetation (1999 and 2000).…”