JPH02312543A - Quality assessmeny of coffee bean - Google Patents

Abstract

PURPOSE:To quickly and accurately judge the grade and roasting degree of coffee bean without relying upon experience and perception by determining the extinction of coffee bean with a near infrared spectrophotometer, calculating a discrimination formula and storing the formula in a memory. CONSTITUTION:Coffee beans of known grade are crushed e.g. to 12 to 42 mesh, uniformly filled in a specimen container and placed and set on a drawer 4. The specimen is irradiated with near infrared radiation and the extinction of the coffee is determined from the standard irradiation intensity and the reflected light intensity. The obtained extinction is stored in the main body 5 of a controller and a discrimination formula is calculated based on a discrimination analysis method (SPSS PC+ program). The extinction of unknown coffee beans is measured and substituted in the discrimination formula and the grade of the coffee is determined based on the obtained numerical value.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for determining the brand and degree of roasting of coffee beans.

<Prior art and its problems> Coffee belongs to the Rubiaceae family and there are approximately 25 species of coffee, but most of them are Arabica and Robusta as practical varieties, and Arabica accounts for the majority in terms of quantity. All the popular beans used for regular coffee are Arabica. And depending on the region of origin, Arabica varieties are mocha,
It is distributed under brands such as Kilimanjaro, Blue Mountain Tele, and Brazil Santos.

Each brand has subtle differences in sourness, bitterness, sweetness, richness, aroma, etc., and brand discrimination is generally done through a cup test (sensory test) conducted by an expert.

In addition, the degree of roasting, which determines the quality of coffee, can be distinguished visually from the three levels of light roast, medium roast, and dark roast in Japan, but there are 8 levels of roasting in the American style. The subtle differences between stages often depend on the experience of experts in determining the degree of bursting of the beans and the degree of browning of the coffee beans themselves.

Of course, there is a method of chemically analyzing the component composition to identify the brand, but the analysis often requires complicated operations and a long time, and in the end it relies on the experience and intuition of experts. It is. Furthermore, the method of determining the degree of roasting using a colorimeter also has drawbacks such as the color of the beans progressing over time, and cannot be said to be a sufficient method for determining the degree of roasting.

<Means for Solving the Problems> In view of the current situation, the present inventors investigated a method for quickly and accurately determining the brand and roasting degree of coffee beans, and found that using a near-infrared spectrometer, The present invention was completed based on the knowledge that this is possible by measuring the absorbance of coffee beans.

That is, the present invention measures the absorbance of coffee beans of known brand using a near-infrared spectrometer, calculates a discriminant from the obtained absorbance, stores this discriminant in a storage device, and measures the absorbance of coffee beans of known brand. This is a coffee bean brand identification method, which is characterized in that the absorbance of coffee beans is measured in the same manner as above, and the measured value is calculated based on the above-mentioned discriminant and visually displayed. The absorbance of the beans is measured using a near-infrared spectrometer, a discriminant is determined from the obtained absorbance, and this discriminant is stored in a storage device, while a sample coffee bean with an unknown degree of roasting is treated in the same manner as above. This method of determining the degree of roasting of coffee beans is characterized in that the absorbance of the roasted coffee beans is measured, and the measured value is calculated based on the above-mentioned discriminant and visually displayed.

The present invention will be explained in detail below.

FIG. 1 is a schematic diagram of an apparatus for carrying out the method of the invention.

This device consists of a near-infrared spectrometer 1 and a control device 2. Inside the cabinet of the near-infrared spectrometer 1, there is a near-infrared spectrometer 3 and a drawer for mounting a sample container to hold a sample to be measured. 4 are arranged.

On the other hand, the control device 2 includes a control device main body 5, a printer 6, a display 7, and a keyboard 8, and the near-infrared spectrometer 1 and the control device 2 are connected.

The near-infrared spectrometer is Infra-Alyzer-500 (
Technicon) etc., but the control device is IBM-PC^T.
(Company 18M) etc. can be cited as a specific example.

For example, in order to identify a brand using such an apparatus, the absorbance of coffee beans of a known brand is first measured. To measure the absorbance of coffee beans, the coffee beans are ground into 12 to 42 meshes, uniformly filled into a broken measurement sample container, and then placed in the drawer 4 and set at a predetermined position. Next, the sample is irradiated with near-infrared rays, and the absorbance is determined from the reference amount of irradiation light and the amount of reflected light.

The absorbance measured here is the absorbance at the following 19 wavelengths. (Unit: nm) 1445, 1680. +722.1734.1759
．． 1778°1818, 1940. 1982. 2
100. 2139. 2180°2190, 220B
, 2230.2270.2310.233B.

2348°-4= The obtained absorbance is stored in the control device main body 5, and a discriminant is created from the absorbance based on the discriminant analysis method (SPSS PC+ program). For coffee beans of unknown brand, only the absorbance at the wavelength used in the discriminant is measured and substituted into the above discriminant, and the brand is determined from the obtained results.

The method for determining the degree of roasting can be performed in exactly the same manner as described above.

<Example> Hereinafter, the present invention will be explained in more detail based on Examples.

Example 1 (Brand identification) Brazil Santos (S), Mocha (M), Colombia (C
), Guatemala (G), Kilimanjaro (2), Manzoline (A), and Blue Mountain (8) were crushed, and the absorbance was measured 30 times in the same manner as above using Infra-Alyzer-500. The following three discriminants, ~
I created D3.

Discriminant: = 0J7X F + + 0.70X F 2
+2.55xF, +1.92XF4
- 0.94XF5-0, l7XF6 + 1.19x
F7+ 0.23XF8- 0.41xFe -0,
D8xF. -0.02xF1+ +0.17XF1
．． -0. l8XF, 4+0, 21X F I5+O,I
IX F I□-〇, 04XF 18+o, oax F
1g D, = 0.77x F 1 + 0.
04X F2-0.03X F3-0.67x
F4-0.54xF5- 1. l2xF6+ 1.72
XFy −0,22XFa 11,50X Fe +
0.45xF+o 0.54xF++
0.38X F 12 + 0.19X F +3-
〇, 28X F 14 + 0.71X F ,, +
0.21XF +s O, I4x F B D3 ” 1.I4X F + + 2.2
8X F2 0.64xF3 + 0.4
9X F a 0.28x F s -1,2
6xFa + 1.41XFT + 0.22XFg
-2,72XF9 - 0.31xF+o -0,2
1xFll + 1.02XF, 2 + 0.9
4XF13 → -0,20X F14 + 0.0
6X F 16 10, I! ixF+6+0
．． 42X F IB + 0.09X F
1eF + Absorbance at 1445 nm F2 Absorbance at 16flOnm F3 Absorbance at 1722 nm F, Absorbance at 1734 nm F5 Absorbance at 1759 nm Fa Absorbance at 1778 nm F7 Absorbance at 1818 nm Fa Absorbance at 1940 nm Fs Absorbance at 19B2 nm F + o Absorbance at 2100 nm F z Absorbance at 2139 nm F 12 Absorbance at 2180 nm F 13 Absorbance at 2190 nm F 14 Absorbance at 2208 nm F 15 Absorbance at 2230 nm F +s Absorbance at 2270 nm F 17 Absorbance at 2310 nm F , a Absorbance at 2336 nm F re 2348 absorbance above nm FIG. 2 shows the result of plotting the values of two equations D1 out of the discriminants, D2, D, on the horizontal axis and the value of D2 on the vertical axis.

As is clear from FIG. 2, each brand of coffee can be clearly distinguished by the discriminant.

Next, when a sample of unknown brand was measured in the same manner as above, it was plotted at point 0 in Figure 2, and this sample was determined to be Blue Mountain.

Example 2 (Determination of degree of roasting) Colombian coffee was roasted with hot air under the following conditions to prepare a sample with a known degree of roasting.

Temperature at time of addition Temperature at end Time Roasting degree 1190-200°C 210°C 15 minutes〃2〃
22016 〃31/23017 〃 4 ノ/
240 1 B〃5〃25019 The absorbance of each sample was measured 30 times in the same manner as in Example 1, and the following three discriminants were created.

(F+, Fa, and Fe are the same as in Example 1) Discriminant % Formula % Results of pro-nod of the above discriminants D+, D2, and D3, with the value of two formulas D1 on the horizontal axis and the value of D2 on the vertical axis The third
As shown in the figure.

On the other hand, when the absorbance of a sample with unknown roasting degree was measured in the same manner as above, it was plotted at 0 points, and the roasting degree of this sample was 3.
It was determined that

Note that by further developing this method, coffee beans that are not judged to be within a certain standard can be judged as non-standard products.

<Effects of the Invention> According to the method of the present invention, the brand and degree of roasting of coffee beans can be quickly and accurately determined without relying on experience or intuition, and is useful for quality control in the coffee bean distribution industry and roasting industry. This is an effective method.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the apparatus used in the present invention, FIG. 2 is a plot diagram of a coffee bean brand discrimination formula, and FIG. 3 is a plot diagram of a roast degree determination formula.

Claims (2)

[Claims] (1) Measure the absorbance of coffee beans of known brand using a near-infrared spectrometer, calculate the discriminant from the obtained absorbance,
This discriminant is stored in a storage device, the absorbance of a sample coffee bean of unknown brand is measured in the same manner as above, and the measured value is calculated based on the discriminant and visually displayed. How to identify bean brands. (2) Measure the absorbance of coffee beans with a known degree of roasting using a near-infrared spectrometer, calculate a discriminant from the obtained absorbance, store this discriminant in a storage device, and A method for determining the degree of roasting of coffee beans, which comprises measuring the absorbance of a sample of coffee beans in the same manner as described above, calculating the measured value based on the discriminant formula, and visually displaying the measured value.