OA21183A - Process for obtaining a drink (coffee) based on roasted date stones. - Google Patents

Abstract

The present invention relates to a process for obtaining a beverage (coffee) based on roasted date stones, or with similar particulate plant materials. Date stones are roasted to develop the characteristic flavor and aroma of the product as used by consumers. The flavor and aroma of raw date stones are undesirable; but when these date pits are roasted, complex thermally induced chemical reactions convert the compounds contained in the pits, such as sugars, amino acids, polysaccharides, proteins, trigonelline, chlorogenic acids and others into more than 800 compounds that collectively provide the desire, extractable flavor, color, and aroma characteristics of roasted kernels. Some components of date stones that do not react during roasting, such as caffeine, contribute to the stimulating action and flavor of roasted date stones, but most of the flavor, color and aroma of Roasted date stones are provided by compounds generated during the reactions induced by roasting.

Description

PROCESS FOR OBTAINING A BEVERAGE (Coffee) BASED ON ROASTED DATE SEEDS.

The present invention relates to a process for obtaining a drink (coffee) based on roasted date stones, or with similar particulate plant materials.

roasted to develop the characteristic flavor and aroma of

5.product as used by consumers.

The flavor and aroma of date stones “Date stones are roasted, reactions _{with the sugars} and amino _acids convert the compounds contained. chlorogenic and other acids in addition to the characteristic aroma of roasted kernels.

’1°5™ foXis by compounds generated during reactions uncontrolled by roasting.

Kernel roasting involves systems of interrelated chemical reactions that proceed along sene and parallel reaction paths.

The rates of these reactions increase markedly, but to varying degrees, as grain temperature increases.

Roasting depends on the temperature of the beans as a function of the time during roasting.

toXion Would significantly gain control over flavor and aroma.

endothermic.

5.Once kernel temperatures reach 160°C, rapid exothermic reactions occur, bean temperatures rise rapidly, and the flavor of the resulting coffee changes very quickly.

Excessive weight loss and undesirable flavor changes occur if roasting is excessively prolonged.

10.Therefore, to quickly complete roasting and deliver coffee of the desired and reliably duplicated quality, the cores are most often quickly cooled (extinguished) as soon as they reach a selected end-roasting temperature.

First, a controlled amount of water is sprayed onto the grains and largely evaporates, providing evaporative cooling.

15.Then the cores are further cooled by forced contact with room temperature air.

Reflectance color is the fraction of incident light of a selected spectral composition that is diffusely reflected from the surface of a suitable sample of roasted, ground and compressed coffee.

2O.The lower the reflectance color, the darker the coffee.

End-of-roasting temperatures correlate well with roasting darkness, measured by reflectance color.

The darkness of the roast, in turn, roughly correlates with the flavor. Some consumers prefer relatively dark, bitter roast coffees; others prefer relatively light, slightly acidic coffees; and still others prefer coffee of intermediate character.

Roasting conditions also influence the apparent density (mass of coffee per unit volume) of roasted date stones.

As explained in more detail below, under certain roasting conditions, date pits can be inflated by the internal pressure of steam and other gases as the bean walls soften at elevated temperatures; such blowing reduces the 3O.apparent density.

The bulk density of the roasted kernels in turn influences the bulk density of the ground product as sold to the consumer.

Kernel roasting therefore requires careful control of many factors that influence the taste and appearance of the product, given that the kernel roasting business is competitive, economic factors such as investment costs, Energy costs and core losses during the process are of great importance.

Wastes released from kernel roasting processes can be a source of pollution. It is important to minimize such pollution while maintaining an economical process and without compromising the quality of the finished product.

All the above-mentioned factors together make roasting date stones a complex and difficult process.

A large number of coffee roasting processes and apparatus have been proposed. Most commercial roasting processes currently in use are carried out at atmospheric pressure by contacting the cores with hot gases such as a hot inert gas, typically nitrogen.

The incoming gas heats the kernels while the outlet gas carries away waste such as lO.balls and gases released during roasting.

Traditional roasting methods can only achieve limited rates of heat transfer to the cores and cannot provide full control of the time and temperature history of the cores.

In addition, traditional roasting processes and apparatus require significant effort and expense to minimize pollution.

Various proposals have been put forward for high pressure roasting systems. Notably, numerous patents issued to Horace L. Smith Jr. describe batch or continuous systems for pressure roasting coffee in rolling fluidized beds or spout beds.

2O.A fluidized bed system directs a gas or other fluid upward through a mass of particles such as coffee beans, so that the particles are held suspended in the rising fluid.

Ideally, the upward flow is almost uniform in all regions of the bed. A spouted bed system uses an upward flow of gas or other fluid concentrated at a few locations within the bed. The particles move upward at these locations 25.and downward at other locations in the bed.

Most of Smith's patents call for the use of low-oxygen pressurized gas circulating in a closed loop through: a heater, a coffee roasting bed in a thick-walled cylindrical chamber, and a cyclonic separator. The cyclone separator removes small particles, commonly called “chaff” from the gas.

3O.Some of Smith's patents use gas pressures up to 300 psig (2.1 MPa gauge). In one specific example, Robustas were roasted at 150 psig to improve their flavor. The roasting gas was heated by indirect contact either with a high temperature heat transfer fluid or with hot gases produced in a fuel furnace.

The present invention meets these needs. One aspect of the invention proposes a drink based on date stones according to a method of roasting these date stones.

Preferred methods according to this aspect of the invention include the steps of placing a load of kernels in a roasting pan having a top, lid and bottom, and directing a hot inlet gas through the kernels from the bottom adjacent said plate placed on charcoal embers to thereby form a fluidized bed of the cores in the plate and provide heat to the cores, whereby an exhaust gas comprising at least a portion of the intake gas thus that roasting by-products will be evacuated from said plate placed on embers

The methods according to this aspect of the invention most preferably comprise the step of trapping the nuclei which are stirred at a regular rate in the plate by the flowing gas using a sieve.

The methods also most preferably include the step of moving a shutter proximate the screen so as to momentarily block the flow of gas through different sectors of the screen.

Claims (5)

1. Process for obtaining a drink (coffee) based on roasted date stones characterized by the steps consisting of: a) loading a load of date stones into a roasting plate having an upper part and a lower part; b) placing this plate on embers so a hot intake gas through the cores 5.circulates from the bottom of the heated plate to thereby provide heat to the cores, and c) trap the kernels in the heated plate, thus rotating the kernels in the plate using a perforated ladle. 2. Method according to claim 1, further characterized by the step of moving a shutter above the heated plate so as to momentarily block the escape of gases through the cores, so that the cores maintained in contact inside the heated plate and using the perforated ladle will uniformly undergo the desired roasting. 3. The method of claim 1, further characterized in that the heating gas consists primarily of non-reactive gas components which are substantially non-reactive with the nuclei. 4. The method of claim 3, further characterized in that said non-reactive gaseous components consist of nitrogen and carbon dioxide. 5. Process for obtaining a drink (coffee) based on roasted date pits according to any preceding claim will allow roasting of the pits in a 20.homogeneous manner for a drink (very good quality coffee) based on roasted date stones.