Naslov
Characterization of Apples and Apple Juices by Determining Organic and Inorganic Nutrients

Autori
Juranović Cindrić, Iva ; Zeiner, Michaela

Vrsta, podvrsta i kategorija rada
Poglavlja u knjigama, znanstveni

Knjiga
Apples: Nutrition, Consumption and Health

Urednik/ci
Cordoba, J. Sancho ; Delgado, Fernando A.

Izdavač
Nova Science Publishers

Grad
Haupauge (NY)

Godina
2012

Raspon stranica
52-73

ISBN
978-1-61942-709-9

Ključne riječi
apples, organic and inorganic nutrients

Sažetak
Apples are a rich source of vitamins and minerals, consumed fresh or in form of various products as it is apple juice, one of the most popular beverages in the world. Considering the nutritional importance of apples numerous investigations have been carried out on focusing mainly on their content of major nutrients like acids, amino acids, minerals, and vitamins. Their mineral content is important for nutritional reasons and toxicological aspects. The concentrations of elements in apple juice, whole apples, as well as in the flesh and peel were determined by inductively coupled plasma – optical emission spectrometry (ICP-OES). Prior to analysis using ICP-OES samples underwent a microwave assisted digestion using HNO3. The accuracy of the method determined by spiking experiments was very good (recoveries 88-115%) and the limits of detection of elements were from 0.01 up to 14.7 μg g-1. One apple contains significant amounts of essential elements, namely up to 1.5 g K, 396 mg Na, 176 mg Ca, 125 mg Mg, 26 µg Mn, 36 µg Sr, corresponding to a percentage of the RDA: 31.9 % of K, 26.4 % of Na, 17.6 % of Ca, 31.2 % of Mg, and 1.1 % of Mn. The quantification of elements in apple juice by ICP-OES after dilution (1:20 v/v) with 2% HNO3 is a simple, fast and reliable method (recoveries 90-110%) and the detection limits of element were sufficient for routine analysis of apple juice samples. One glass of apple juice (200 mL) can offer up to 60 mg Ca, 5 µg Cr, 180 µg Fe, 130 mg K, 12 mg Mg, 76 µg Mn, 5 mg Na, and 90 µg Zn, corresponding to 6% of the RDA of Ca ; 15% of the RDA of Cr ; 3% of the RDA of K, Mg, and Mn ; and <1% of the RDA of Fe, Na, and Zn. Polyphenols are also important constituents of apples since they may play a role in the prevention of certain forms of human cancer. The diversity of apple phenolics is still an analytical challenge. Solvent extraction procedure for accumulation of phenolic compounds from Idared apples was optimized (extraction recoveries 85-115%) for final high-performance liquid chromatographic analysis (HPLC) with UV detector. Significant amounts of phenolic compounds are present in apples and derived food stuff. The sensitivity of HPLC-UV analysis ranged from 0.005 µg/mL for caffeic acid to 0.09 µg/mL for quercetin. (-)- epicatechin, quercetin, genistein, (-)- gallocatechin-3-gallate, p-coumaric acid and caffeic acid were identified in apple juice extracts in concentration of 13.6 mg/L, 1.5 mg/L, 0.28 mg/L, 0.23 mg/L, 0.71 mg/L and 0.32 mg/L, respectively. The antioxidant capacity and the total phenol content of apples were determined by UV-Vis spectrometry after extraction using an organic solvent. The overall picture of the nutrients obtained for apples and derived food stuff underline their importance for the human diet and justify intensive research in this field.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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