Cultivar and growing site influences on sensory attributes of mandarin fruits and their juices

Istraživanjem je proučavano 4 sorte mandarina vrste C. unshiu Marc. (Okitsu, Kawano Wase, Zorica, Chahara) ubranih na zemljopisnim područjima rijeke Neretve (1, 2, 3, 4, 5, 7 i 9) te jedne sorte (Okitsu) ubrane na području Turske i Španjolske. Svrhe rada: (a) ispitati utjecaj sorte, područja uzgoja, roka i godine berbe na instrumentalno izmjerenu boju, teksturu te senzorska svojstva, (b) utvrditi postoji li korelacija između izmjerenih senzorskih i instrumentalnih svojstava teksture i boje (c) ispitati utjecaj predtretmana i roka berbe na parametre kvalitete i senzorska svojstva soka od mandarine. Istraživanje ima 2 dijela od kojih je 1. dio proveden u 2009., a 2. u 2010. Definiranje svojstava mandarina pokriveno djelokrugom ovog doktorskog rada uključuje senzorska svojstva (n=679), svojstva boje (kolorimetrijski) (n=468) i teksture (mjereno teksturometrom) (n=234). Mjerena svojstva sokova uključuju senzorska svojstva (n=162), svojstva boje (kolorimetrijska) (n=54) i viskoznost (mjereno rotacionim viskozimetrom) (n=126). Senzorsko ocjenjivanje je izvršeno prema principima kvalitativne deskriptivne analize (QDA). Diskretne kategoričke varijable su analizirane χ2 testovima, a kontinuirane neparametričkim t-testovima. Analiza varijance je rađena neparametrijskom ANOV-om, a linearna ovisnost Pearsonovom analizom korelacije. Nivo signifikantnosti za sve testove bio je α≤0.05. Dobiveni podaci su analizirani SPSS-om (v.17). Senzorska svojstva i određeni rezultati za boju i teksturu instrumentalno izmjerenu, variraju obzirom na sorte, područja uzgoja te godinu i rok berbe. Selektirana senzorska svojstva (boje i teksture) imaju korelaciju s instrumentalno izmjerenom bojom i teksturom. Na primjer, Okitsu mandarine s više žutocrvene boje određene kolorimetrom dobile su višu senzorske ocjenu boje, dok su one žilavije za žvakanje dobile manje bodova pri senzorskom ocjenjivanju teksture. Hrvatske mandarine imaju bolje ocijenjena senzorska svojstva od mandarina iz Španjolske i Turske. Prosječno iskorištenje dobiveno prilikom prerade mandarina (73%) nadmašilo je teorijsko za 10%. Na temelju analize, enzimsko tretiranje mandarina prije prešanja nije neophodno, ali nije negativno utjecalo na senzorska svojstva soka. Od ispitivanih svojstava sokova senzorski je najbolje ocjenjena boja, a vrijednosti izmjerene kolorimetrom također ukazuju na izvanrednu očuvanost boje tijekom prerade.This research studied 4 cultivars of C. unshiu Marc. mandarin (Okitsu, Kawano Wase, Zorica, Chahara) harvested at the planting positions of Neretva river (1, 2, 3, 4, 5, 7 and 9), Spain and Turkey (Okitsu). Objectives of this study were: (a) to examine influences of different cultivars, planting position, terms of harvests and seasonal effects on instrumentally measured color, texture and sensory properties, (b) to determine whether or not is there a correlation between the instrumentally measured texture and color and their sensory counterparts, and (c) to examine influences of various pretreatments and terms of harvests on quality parameters and sensory characteristics of mandarin juices. The survey had 2 parts, first part done in 2009, a second one in 2010. The scope of this dissertation covers evaluation of sensory (n=679), colorimetric (n=468) and texture (n=234) characteristics of mandarin. Similarly, juices were evaluated on sensorics (n=162), colorimetry (n=54) and viscosity (n=126). Sensory evaluation was approached by quantitative descriptive analysis (QDA). Discrete categorical variables were analyzed using χ2 tests, and continuous variables using nonparametric t-tests. Nonparametric ANOVA was used for analysis of variance, and Pearson's correlation analysis measured the strength of associations. The significance levels for all tests were α=0.05 or less. Analyses were done with SPSS (v.17). Sensory characteristics and instrumentally measured color and texture vary with various cultivars, planting positions, seasons and terms of harvest. Selected sensory characteristics (color and texture) logically correlated with instrumentally measured color and texture. For instance, more yellowish-red Okitsu mandarins received higher score in color sensory evaluation, on the other hand the chewier that they were the lesser score they received. Croatian mandarins have better sensory properties than mandarins from Spain and Turkey. Average yield obtained during the processing of mandarins (73%) exceeded the theoretical for 10%. Based on data, enzymatic treatment of mandarins prior pressing was not necessary, but did not adversely affected juice sensory properties. Color of juices had the best ratings of all tested sensory characteristics, while the excellent preservation of the color during processing was confirmed by colorimeter