Sensory properties of modified aronia (Aronia mitschurinii) juices
Vanag, Anita (2017-06-12)
Sensory properties of modified aronia (Aronia mitschurinii) juices
Vanag, Anita
(12.06.2017)
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Turun yliopisto
Kuvaus
Siirretty Doriasta
Tiivistelmä
Aronia, also known as chokeberry, is cultivated in many countries as both ornamental shrubs and for harvesting berries, which are usually used to produce juices, jams, teas, etc. Aronia berries are rich in polyphenols, low in organic acids, and have one of the highest concentrations of sorbitol, which means they can be potentially used for medicinal and therapeutic purposes. However, due to strong and mostly unfamiliar orosensory properties of the berry, commercially aronia is mostly used in blended juices and not as a pure juice. The aim of this work was to analyze sensory properties (appearance, odor and taste) of modified aronia (Aronia mitschurinii) juices because they are less studied than chemical composition of this berry.
Two different juices were made from crushed berries of two harvest years 2012 and 2016 without (I) and with (II) pectinolytic enzyme treatment. Sensory properties of the juices were modified by adding sucrose (1%, 2%, or 4%) or citric acid (0.05%, or 0.15%) and by diluting juices with water 1:2. Modified juice samples as well as two commercially available aronia juices were studied in a three-session sensory evaluation in controlled lab environment (ISO 8589). In the 1st session 32 consumers evaluated 13 samples and in the 2nd session 28 consumers evaluated another 7 samples using projective mapping as an evaluation method. In the 3rd session 7 trained panelists created qualitative profiles for 7 samples that were previously evaluated by consumers. Finally, a gas chromatography analysis of sugars and acids present in studied juices was carried out.
Sensory evaluations showed a clear difference in the color, odor, and taste of juices prepared with and without enzyme treatment. Juices pressed with enzymatic assistance were described as “unpleasant”, having “almond”, “nutty”, “oat”, “stale” and “astringent” odor and taste among other descriptions. Juices with the highest added concentration of sucrose were chosen as the most “pleasant”, while others were said to be “too sour” and “astringent”. The harvest year also affected the sensory properties of juices. Non-enzyme juices made from 2012 berries were considered “lighter” and “more pleasant” in taste, while juices made from 2016 berries had “stronger” and “astringent” taste. Commercial juices were found to be “sour” and in general had different flavor and taste.
Gas chromatography analysis of sugars and acids in aronia juices showed that the main sugars are glucose, sorbitol and fructose, and main organic acids are malic and quinic acids.
Two different juices were made from crushed berries of two harvest years 2012 and 2016 without (I) and with (II) pectinolytic enzyme treatment. Sensory properties of the juices were modified by adding sucrose (1%, 2%, or 4%) or citric acid (0.05%, or 0.15%) and by diluting juices with water 1:2. Modified juice samples as well as two commercially available aronia juices were studied in a three-session sensory evaluation in controlled lab environment (ISO 8589). In the 1st session 32 consumers evaluated 13 samples and in the 2nd session 28 consumers evaluated another 7 samples using projective mapping as an evaluation method. In the 3rd session 7 trained panelists created qualitative profiles for 7 samples that were previously evaluated by consumers. Finally, a gas chromatography analysis of sugars and acids present in studied juices was carried out.
Sensory evaluations showed a clear difference in the color, odor, and taste of juices prepared with and without enzyme treatment. Juices pressed with enzymatic assistance were described as “unpleasant”, having “almond”, “nutty”, “oat”, “stale” and “astringent” odor and taste among other descriptions. Juices with the highest added concentration of sucrose were chosen as the most “pleasant”, while others were said to be “too sour” and “astringent”. The harvest year also affected the sensory properties of juices. Non-enzyme juices made from 2012 berries were considered “lighter” and “more pleasant” in taste, while juices made from 2016 berries had “stronger” and “astringent” taste. Commercial juices were found to be “sour” and in general had different flavor and taste.
Gas chromatography analysis of sugars and acids in aronia juices showed that the main sugars are glucose, sorbitol and fructose, and main organic acids are malic and quinic acids.