阅读说明：本技术 一种澄清、透亮速溶咖啡的生产方法 (Production method of clear and bright instant coffee ) 是由 赵伟文 于 2021-01-28 设计创作，主要内容包括：本发明属于咖啡生产技术领域,具体涉及一种澄清、透亮速溶咖啡的生产方法,包括微波烘焙、研磨、浸泡、过滤、冷冻真空干燥等步骤,本发明使用微波进行咖啡前期烘焙处理,效率高,通过本发明设定的微波烘烤参数,烘焙获得的均匀度好,无局部焦黑现象,且已有研究表明,通过微波烘焙得到的咖啡豆能较好的保持咖啡豆的风味,且微波具有极强的穿透能力,使微波加热具有与常规加热不同的特性,微波加热是通过物质中的水分子强烈吸收微波能,致使介质内分子急剧摩擦,以显著的热效应使物料内部生热,形成体热源来实现的,在此影响下,咖啡豆的破裂力会显著增加,由此将咖啡烘焙后,细胞破壁率>95%,对咖啡豆的有效浸出物提高45～48%,浸泡时间缩短50%。(The invention belongs to the technical field of coffee production, and particularly relates to a method for producing clear and bright instant coffee, which comprises the steps of microwave baking, grinding, soaking, filtering, freezing and vacuum drying and the like, wherein microwaves are used for carrying out early-stage baking treatment on the coffee, the efficiency is high, the uniformity obtained by baking is good and no local scorching phenomenon exists through the set microwave baking parameters of the invention, and the research shows that the coffee beans obtained by microwave baking can better keep the flavor of the coffee beans, the microwaves have extremely strong penetrating power, so that the microwave heating has the characteristics different from the conventional heating, the microwave heating is realized by strongly absorbing microwave energy through water molecules in substances, so that molecules in a medium are rapidly rubbed, the heat inside the materials is generated by obvious heat effect, and a body heat source is formed, and under the influence, the breaking force of the coffee beans can be obviously increased, therefore, after the coffee is roasted, the cell wall breaking rate is over 95 percent, the effective extract of the coffee beans is improved by 45-48 percent, and the soaking time is shortened by 50 percent.)

1. A production method of clear and bright instant coffee is characterized by comprising the following steps:

s1, roasting the pretreated coffee beans by using a tunnel type microwave machine;

s2, grinding the roasted coffee beans into superfine powder of 600-1500 meshes by using a cell wall breaking machine;

s3: soaking the raw materials in hot water at 90-95 ℃ for 10-20min according to the solid-liquid ratio of 1: 8-10, filtering by using a centrifugal machine, and naturally cooling the filtrate to room temperature to obtain filtrate A;

s4: performing vacuum filtration on the cooled filtrate A by using a filter membrane matched with a ceramic mould and an ultrafiltration mould to obtain filtrate B;

s5: and (3) freezing the cooled filtrate B to 50-60 ℃ below zero, carrying out freeze vacuum drying to obtain coffee crystal powder, granulating and packaging.

2. The method as claimed in claim 1, wherein the microwave power in step S1 is 300-500W, the baking temperature is 200-220 ℃, the baking time is 10-20min, and the bulk density is 0.2-0.5g/cm²。

3. The method of claim 1, wherein the roasted coffee beans are ground to 1000 mesh ultra fine powder by using a cell wall breaking machine in step S2.

4. The method of claim 1, wherein in step S4, the ceramic membrane has a pore size of 0.2 μm and the ultrafiltration membrane has a pore size of 20 kilodaltons.

5. The method of claim 1, wherein in step S5, the coffee grinds are granulated using a roller granulator.

6. Use of coffee granulate obtained according to any one of the methods for producing a clear, bright instant coffee according to claims 1 to 5 in a coffee product.

Technical Field

The invention belongs to the technical field of coffee production, and particularly relates to a production method of clear and bright instant coffee.

Background

Coffee is one of three crops in the world, and gradually becomes an indispensable daily drink for modern people due to unique mellow taste and refreshing and exciting effects. Currently, over 70 countries and regions have produced coffee, and approximately 15 million people drink daily. In 1901, instant coffee was invented by Saetori Kato, a japanese scientist working in chicago, usa, and a technology for mass production of instant coffee was invented by George Constant Louis Washington, and was marketed in 1910. The instant coffee is convenient to eat, high in quality and low in price in home and travel, is loved by consumers, and the production and sales volume is increased year by year.

With the change of consumption habits, the application fields of coffee are more and more, the coffee ingredient quality with coffee flavor is particularly required in the processing process of some special high-quality foods, the existing processing method of instant coffee comprises the steps of pretreatment, roasting, grinding, extraction, concentration and drying of coffee beans, and under the existing processing technology, the obtained concentrated coffee contains more insoluble particles and is darker in color and not suitable for the processing requirements of some food fields.

Disclosure of Invention

The invention mainly aims to provide a production method of clear and bright instant coffee so as to meet the requirements of special food processing.

In order to achieve the above purpose, the invention provides the following technical scheme:

a method for producing clear and bright instant coffee comprises the following steps:

s1, roasting the pretreated coffee beans by using a tunnel type microwave machine;

s2, grinding the roasted coffee beans into superfine powder of 600-1500 meshes by using a cell wall breaking machine;

s3: soaking the raw materials in hot water at 90-95 ℃ for 10-20min according to the solid-liquid ratio of 1: 8-10, filtering by using a centrifugal machine, and naturally cooling the filtrate to room temperature to obtain filtrate A;

s4: performing vacuum filtration on the cooled filtrate A by using a filter membrane matched with a ceramic mould and an ultrafiltration mould to obtain filtrate B;

s5: and (3) freezing the cooled filtrate B to 50-60 ℃ below zero, carrying out freeze vacuum drying to obtain coffee crystal powder, granulating and packaging.

Further, the step S1 is a stepThe wave power is 300-500W, the baking temperature is 200-220 ℃, the baking time is 10-20min, and the bulk density is 0.2-0.5g/cm²。

Further, in the step S2, the roasted coffee beans are ground into ultra-fine powder of 1000 mesh using a cell wall breaking machine.

Further, in step S4, the pore size of the ceramic membrane is 0.2 μm, and the pore size of the ultrafiltration membrane is 20 kilodaltons.

Further, in step S5, the coffee powder is granulated by using a roller press type granulator.

The invention has the following advantages:

according to the microwave roasting treatment method, microwaves are used for roasting coffee in the early stage, the efficiency is high, the roasting uniformity is good through the microwave roasting parameters set by the microwave roasting treatment method, the local scorching phenomenon is avoided, and researches show that coffee beans obtained through microwave roasting can well keep the flavor of the coffee beans, the microwaves have extremely strong penetrating power, so that the microwave heating has different characteristics from conventional heating, the microwave heating is realized by enabling water molecules in substances to strongly absorb microwave energy, causing medium molecules to rapidly rub, enabling the materials to generate heat inside with obvious heat effect, and forming a body heat source, under the influence, the rupture force of the coffee beans can be obviously increased, so that the cell wall breaking rate is higher than 95% after the coffee is roasted, the effective extract of the coffee beans is improved by 45-48%, and the soaking time is shortened by 50%.

The coffee is subjected to superfine crushing, so that the extract is increased after the coffee is dissolved, the effective extraction rate reaches 36 percent, the coffee aroma substance is kept to 90 percent, which is 3 to 4 times of that of the traditional instant coffee, the coffee is subjected to hot extraction, hot and cold filtration twice, freeze drying is adopted, compared with the conventional instant coffee extraction, the method reduces the concentration step, and the filtrate is in an unsaturated transition state under the condition that the solid-liquid ratio is 1: 8-10, under the condition, the unsaturated material has a loose and uniform prefabricated pore structure inside, the connectivity among pores is better, in the freeze-drying process, along with the continuous increase of external environment heat intensity, inside ice crystal sublimation is with higher speed, and vapor after the sublimation can in time migrate away in prefabricated hole, has avoided melting vapor accumulation of inside ice crystal, is favorable to the continuation of ice crystal to sublime. Therefore, unsaturated materials have a more stable structure and a wider operating temperature range during freeze-drying compared to saturated materials.

Compared with the traditional instant coffee, the coffee bean is subjected to superfine crushing and twice filtering, the obtained molecular particle size is smaller, the dissolubility is higher, and the coffee crystal powder obtained after freeze drying is granulated by a roller pressing type granulator due to stable structure, so that longer storage time can be obtained without adding any preservative.

Drawings

FIG. 1 is a graph showing a comparison between comparative example 1 and example 3 of the present invention after dissolution of coffee.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

S1, roasting the green coffee beans by a tunnel type microwave machine, wherein the microwave power is 300-500W, the roasting temperature is 200-220 ℃, the roasting time is 10min, and the bulk density is 0.2g/cm²。

S2, grinding the roasted coffee beans into superfine powder of 1000 meshes by using a cell wall breaking machine;

s3: soaking the raw materials in hot water at 90-95 ℃ for 10min according to the solid-liquid ratio of 1:10, filtering by using a centrifugal machine, and naturally cooling the filtrate to room temperature to obtain filtrate A;

s4: performing vacuum filtration on the cooled filtrate A by using a filter membrane matched with a ceramic membrane and an ultrafiltration membrane to obtain a filtrate B, wherein the pore diameter of the ceramic membrane is 0.2 micron, and the pore diameter of the ultrafiltration membrane is 20 ten thousand daltons;

s5: and (3) freezing the cooled filtrate B to 50-60 ℃ below zero, and carrying out freeze vacuum drying to obtain coffee crystal powder, wherein the coffee crystal powder is granulated and packaged by adopting a roller press type granulator.

Example 2

S1, roasting the green coffee beans by a tunnel type microwave machine, wherein the microwave power is 300-500W, the roasting temperature is 200-220 ℃, the roasting time is 20min, and the bulk density is0.5g/cm²。

S2, grinding the roasted coffee beans into superfine powder of 1000 meshes by using a cell wall breaking machine;

s3: soaking the raw materials in hot water at 90-95 ℃ for 20min according to the solid-liquid ratio of 1:9, filtering by using a centrifugal machine, and naturally cooling the filtrate to room temperature to obtain filtrate A;

s4: performing vacuum filtration on the cooled filtrate A by using a filter membrane matched with a ceramic membrane and an ultrafiltration membrane to obtain a filtrate B, wherein the pore diameter of the ceramic membrane is 0.2 micron, and the pore diameter of the ultrafiltration membrane is 20 ten thousand daltons;

s5: and (3) freezing the cooled filtrate B to 50-60 ℃ below zero, and carrying out freeze vacuum drying to obtain coffee crystal powder, wherein the coffee crystal powder is granulated and packaged by adopting a roller press type granulator.

Example 3

S1, roasting the green coffee beans by a tunnel type microwave machine, wherein the microwave power is 300-500W, the roasting temperature is 200-220 ℃, the roasting time is 15min, and the bulk density is 0.3g/cm²。

S2, grinding the roasted coffee beans into superfine powder of 1000 meshes by using a cell wall breaking machine;

s3: soaking the raw materials in hot water at 90-95 ℃ for 15min according to the solid-liquid ratio of 1:10, filtering by using a centrifugal machine, and naturally cooling the filtrate to room temperature to obtain filtrate A;

s4: performing vacuum filtration on the cooled filtrate A by using a filter membrane matched with a ceramic membrane and an ultrafiltration membrane to obtain a filtrate B, wherein the pore diameter of the ceramic membrane is 0.2 micron, and the pore diameter of the ultrafiltration membrane is 20 ten thousand daltons;

s5: and (3) freezing the cooled filtrate B to 50-60 ℃ below zero, and carrying out freeze vacuum drying to obtain coffee crystal powder, wherein the coffee crystal powder is granulated and packaged by adopting a roller press type granulator.

Example 4

S1, roasting the green coffee beans by a tunnel type microwave machine, wherein the microwave power is 300-500W, the roasting temperature is 200-220 ℃, the roasting time is 15min, and the bulk density is 0.3g/cm²。

S2, grinding the roasted coffee beans into superfine powder of 600 meshes by using a cell wall breaking machine;

s3: soaking the raw materials in hot water at 90-95 ℃ for 15min according to the solid-liquid ratio of 1:10, filtering by using a centrifugal machine, and naturally cooling the filtrate to room temperature to obtain filtrate A;

s4: performing vacuum filtration on the cooled filtrate A by using a filter membrane matched with a ceramic membrane and an ultrafiltration membrane to obtain a filtrate B, wherein the pore diameter of the ceramic membrane is 0.2 micron, and the pore diameter of the ultrafiltration membrane is 20 ten thousand daltons;

s5: and (3) freezing the cooled filtrate B to 50-60 ℃ below zero, and carrying out freeze vacuum drying to obtain coffee crystal powder, wherein the coffee crystal powder is granulated and packaged by adopting a roller press type granulator.

Example 5

S1, roasting the green coffee beans by a tunnel type microwave machine, wherein the microwave power is 300-500W, the roasting temperature is 200-220 ℃, the roasting time is 15min, and the bulk density is 0.3g/cm²。

S2, grinding the roasted coffee beans into superfine powder of 800 meshes by using a cell wall breaking machine;

s3: soaking the raw materials in hot water at 90-95 ℃ for 15min according to the solid-liquid ratio of 1:10, filtering by using a centrifugal machine, and naturally cooling the filtrate to room temperature to obtain filtrate A;

s4: performing vacuum filtration on the cooled filtrate A by using a filter membrane matched with a ceramic membrane and an ultrafiltration membrane to obtain a filtrate B, wherein the pore diameter of the ceramic membrane is 0.2 micron, and the pore diameter of the ultrafiltration membrane is 20 ten thousand daltons;

s5: and (3) freezing the cooled filtrate B to 50-60 ℃ below zero, and carrying out freeze vacuum drying to obtain coffee crystal powder, wherein the coffee crystal powder is granulated and packaged by adopting a roller press type granulator.

Example 6

S1, roasting the green coffee beans by a tunnel type microwave machine, wherein the microwave power is 300-500W, the roasting temperature is 200-220 ℃, the roasting time is 15min, and the bulk density is 0.3g/cm²。

S2, grinding the roasted coffee beans into superfine powder of 1200 meshes by using a cell wall breaking machine;

s3: soaking the raw materials in hot water at 90-95 ℃ for 15min according to the solid-liquid ratio of 1:10, filtering by using a centrifugal machine, and naturally cooling the filtrate to room temperature to obtain filtrate A;

s4: performing vacuum filtration on the cooled filtrate A by using a filter membrane matched with a ceramic membrane and an ultrafiltration membrane to obtain a filtrate B, wherein the pore diameter of the ceramic membrane is 0.2 micron, and the pore diameter of the ultrafiltration membrane is 20 ten thousand daltons;

s5: and (3) freezing the cooled filtrate B to 50-60 ℃ below zero, and carrying out freeze vacuum drying to obtain coffee crystal powder, wherein the coffee crystal powder is granulated and packaged by adopting a roller press type granulator.

Comparative example 1

Pre-treating, namely selecting the coffee beans with good quality;

baking: baking for half an hour at 90-100 ℃ by using a baking machine;

grinding: grinding and crushing the treated coffee by a roller disc grinder;

pulping: adding about three times of hot water of 95 ℃ into coffee, and stirring uniformly to fully dissolve ground slag in the hot water;

leaching: leaching the coffee liquid by using a leaching machine;

concentration: concentrating the extracted coffee liquid to 60-70%;

and (3) freeze drying: the coffee thick liquid is dried into powder by spraying (220-240 ℃).

Comparative example 2

Pre-treating, namely selecting the coffee beans with good quality;

baking: roasting the green coffee beans by a tunnel type microwave machine, wherein the microwave power is 500W at 200 ℃ and 220 ℃, the roasting time is 15min, and the bulk density is 0.3g/cm²；

Grinding: grinding and crushing the treated coffee by a roller disc grinder;

pulping: adding about three times of hot water of 95 ℃ into coffee, and stirring uniformly to fully dissolve ground slag in the hot water;

leaching: leaching the coffee liquid by using a leaching machine;

concentration: concentrating the extracted coffee liquid to 60-70%;

and (3) freeze drying: freeze drying the coffee concentrate to obtain powder.

Sensory evaluation

The sample is placed in a clean white porcelain plate, placed under natural light, and is visually observed by three persons, smelled by nose, dissolved and tasted by mouth, and the average score is obtained.

According to the grading result, the color of the product obtained by the traditional processing method is obviously not deep, specifically, as shown in figure 1, No. 1 is the display of the product obtained in comparative example 1 after being dissolved, and No. 2 is the display of the product obtained in embodiment 3 of the invention after being dissolved, the product obtained by the invention has clear and transparent color, and can still keep the fragrance and achieve excellent quality in taste and appearance under the condition of reduced color degree.

Caffeine determination (using the determination method as the current standard GB 5009.139-2014)

Weighing 1g (accurate to 0.001 g) of a uniform sample which is crushed to be less than 30 meshes, putting the uniform sample into a 250 mL conical flask, adding 200 mL of water, boiling water bath for 30 min, shaking occasionally, taking out running water for cooling for 1 min, adding 5g of magnesium oxide, shaking, putting into the boiling water bath for 20min, taking out the conical flask, cooling to room temperature, transferring into a 250 mL volumetric flask, adding water to a constant volume to reach a scale (the caffeine content in the sample solution is in a standard curve range), shaking uniformly, standing, taking supernatant, and filtering by a microporous filter membrane for later use.

And respectively injecting the standard series working solution into a liquid chromatograph, measuring corresponding peak areas, and drawing a standard curve by taking the concentration of the standard working solution as an abscissa and the peak area as an ordinate.

Injecting the sample solution into a liquid chromatograph, determining the quality by retention time, simultaneously recording peak area, obtaining the concentration of caffeine in the liquid to be detected according to a standard curve, carrying out parallel determination for no less than two times, and then calculating according to a standard calculation formula.

As can be seen from the table above, the caffeine content measured in the embodiment of the invention is much higher than that of the comparative example, and the coffee is broken to a certain degree, which is beneficial to extracting the caffeine.

Solubility determination (using the determination method of the current standard GB 5413.29-2010)

Weighing 5g (accurate to 0.01 g) of sample into a 50 mL beaker, dissolving the instant coffee powder in a 50 mL centrifuge tube with 38 mL water at 25-30 ℃ for several times, and plugging. Placing the centrifuge tube in 30 deg.C water, keeping the temperature for 5min, taking out, and shaking for 3 min. Centrifuging at proper speed for 10min to precipitate insoluble substances. The supernatant was decanted and the walls were wiped clean with a cotton swab. Then 38 mL of water with the temperature of 25-30 ℃ is added, a plug is added, and the mixture is shaken up and down to suspend the sediment. Centrifuging in centrifuge for 10min, removing supernatant, and wiping tube wall with cotton plug. The precipitate was washed with a small amount of water into a weighing dish of known mass, the water content of the dish was evaporated to dryness on a boiling water bath and then transferred to an oven at 100 ℃ to dry to constant weight (the difference in mass between the last two times does not exceed 2 mg). And then calculated using standard calculation formulas.

The solubility test table shows that the product obtained by the invention has better solubility at room temperature, and is suitable for dissolving and processing various products at room temperature.