Quantitative Analysis of Raw Apple Juices Using near Infrared,Fourier-Transform near Infrared and Fourier-Transform Infrared Instruments: A Comparison of Their Analytical Performances

Abstract

Several near infrared (NIR) and mid-infrared (MIR) instruments were evaluated for the qualitative and quantitative analysis of raw apple juices prepared from different varieties and cultivars: (i) NIR with a dispersive monochromator using transmittance and a cuvette (NIR transmittance), (ii) NIR with a dispersive monochromator using transflectance (NIR reflectance), (iii) NIR with Fourier-transform interferometer and a transmittance fibre optic (FT-NIR), (iv) MIR Fourier-transform interferometer and a transmittance flow cell (FT-MIR). Principal component analysis (PCA) can be used to detect abnormal juices and outliers. The PCA scores can be used to provide a rough estimate of the characteristics of the juices. It is shown that the best analytical results are achieved by the FT-MIR technique and by NIR transmittance. The accuracy obtained in transflectance (NIR reflectance) or by the FT-NIR technique are lower. The analysis of the main components of apple juices (malic acid, total sugars, sucrose, glucose, fructose) leads to valuable analytical results [R² > 0.95 and standard deviation/standard error of calibration (SD/SEC) ratio ranging from 4.2 to 10.2]. Tannic acid is hard to predict whatever the technique of spectral acquisition. pH is also rather difficult to predict but can be used to perform a three groups classification (SD/SEC between 2.5 and 3.0). The specific gravity can also be predicted in most cases.

Keywords

Apple juices sugars malic acid tannic acid NIR reflectance NIR transmittance FT-NIR FT-IR

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References

Ooghe

and Cornil

, in Progress in the Authenticity Assurance for Fruit Juices, Ed by Funk

and Rieth

, SGF Symposium, Parma, Italy, 6–9 September, 107–128 (1994).

De Léne Mirouze

Boulou

Dupuy

Meurens

Huvenne

J.P.

and Legrand

, Appl. Spectrosc. 47(8), 1187 (1993).

Meurens

, in Making Light Work: Advances in Near Infrared Spectroscopy, Ed by Murray

and Cowe

4^th ICNIRS, Aberdeen, Scotland. VCH, Weinheim, pp. 41–44 (1991).

Alfaro

Meurens

and Birth

, Appl. Spectrosc. 44(6), 979 (1990).

Meurens

Foulon

and Acta

, Cerevisia 20(3), 33 (1995).

Twoney

Downey

and McNulty

, J. Sci. Food Agric. 67, 77 (1995).

Scotter

and Legrand

, in Progress in the Authenticity Assurance for Fruit Juices, Ed by Funk

and Rieth

SGF Symposium, Parma, Italy, 6–9 September, pp. 253–270 (1994).

Meurens

Dupuy

De Léne Mirouze

Legrand

and Huvenne

J.P.

, in Bridging the Gap between Data Analysis and NIR Applications, Ed by Hildrum

Isaksson

Næs

and Tandberg

5^th ICNIRS, Haugesund, Norway. Ellis Horwood Ltd, Chichester, pp. 41–49 (1992).

Defernez

Kemsley

and Wilson

, J. Agric. Food Chem. 43, 109 (1995).

10.

Smith

and Runtz

, in Methods to Detect Adulteration of Fruit Juices and Beverages, Vol. 1, Ed by Nagy

and Wade

AG Science Inc., Auburndale, FL, USA, pp. 112–119 (1995).

11.

Lateur

and Populer

, Euphytica 77, 147 (1994).

12.

Saag

, in HPLC in Food Analysis. Academic Press Ltd, pp. 185–258 (1988).

13.

AOAC

“Tannin Official Final Action” in American Official Analytical Chemists, 13th edition, 9098, p. 158 (1980).

14.

AOAC

“Titrable Acidity Final Action” in American Official Analytical Chemists, 13th edition, 22060, p. 366 (1980).

15.

Shenk

and Westerhaus

, Analysis of Agriculture and Food Products by Near Infrared Reflectance Spectroscopy. Infrasoft International, Port Matilda, PA, USA, p. 103 (1993).

16.

Barnes

Dhanoa

and Lister

, Appl. Spectrosc. 39(5), 772 (1989).

17.

Williams

and Sobering

, in Near Infrared Spectroscopy: Bridging the Gap between Data Analysis and NIR Applications, Ed by Hildrum

Isaksson

Næs

and Tandberg

5^th ICNIRS, Haugesund, Norway. Ellis Horwood Ltd, Chichester, pp. 441–446 (1992).

18.

Williams

and Norris

, in Near Infrared Technology in the Agricultural and Food Industries, Ed by Williams

and Norris

American Association of Cereal Chemists, St Paul, MN, pp. 246 (1987).

19.

Lanher

, FT-IR Analysis of Added Sucrose in Orange Juice. Technical note, Anadis Instruments, Madison, WI, p. 15 (1994).