JP6096546B2 - Mulberry tea production method - Google Patents

Description

  The present invention relates to a method for producing mulberry tea, and more particularly, to a method for producing mulberry tea with improved taste while suppressing a decrease in the amount of active ingredients contained in mulberry leaves as a raw material.

  Mulberry leaves have been widely used as sericulture feed in the past, but in recent years the demand for sericulture has drastically decreased. On the other hand, mulberry leaves are known to have medicinal effects in the treatment of diabetes and blood pressure suppression in Kampo medicines, so they should be dried and decocted to make mulberry tea, which can be taken for the purpose of health promotion. Has been done.

  In mulberry leaves, protein, dietary fiber, various vitamins, flavonoids, polyphenols, physiologically active components such as plant sterols, minerals such as calcium, magnesium, potassium, iron and zinc, amino acids, etc. This is because a substance that inhibits the activity of α-glucosidase (AGH) called 1-deoxynojirimycin (DNJ) is contained.

  Among these ingredients, DNJ is said to be contained only in mulberry leaves in plants, but in particular, the content of “Morus australis Poir” grown in Okinawa and Amami is high in mulberry leaves, When the present inventors examined, the amount of 2.5-4 times as much as the mainland mulberry leaf was contained.

  As mentioned above, mulberry leaves can be used as a drink for health purposes. However, it is not enough to drink them every day, and it is not enough to be healthy. It is rare.

  By the way, mulberry tea obtained by simply drying mulberry leaves in the sun or in the shade has a blue smell and a unique taste, and it is extremely difficult to drink, so methods for removing the blue smell and unique taste have been studied. ing. For example, Patent Document 1 discloses a production method in which fresh mulberry leaves are steamed and twisted and then stirred (roasted) at 160 to 280 ° C.

  Although the roasted mulberry tea has a slight improvement in blue odor, it is far from the savory taste and scent of the roasted tea leaves. Presents a problem that is difficult to drink. Moreover, even if the manufacturing method of black tea and oolong tea known as fermented tea was applied to mulberry leaves as it was, the blue odor did not disappear and the taste was not improved.

  In recent years, many new techniques for removing the blue odor and unique taste of mulberry leaves have been reported (Patent Documents 2 to 9). However, none of these techniques can be said to be sufficient in terms of taste or retention of active ingredients.

JP-A-3-65167 JP-A-5-153941 JP 9-206019 A JP 2002-95441 A JP 2002-171918 A JP 2006-101732 A JP2007-60908 JP2007-89554 JP2009-153530

  The present invention has been made in view of such circumstances, and its object is to provide a method for producing mulberry tea with improved taste while suppressing a decrease in the content of active ingredients contained in mulberry leaves, particularly DNJ. To do.

  The present inventor paid attention to mulberry leaves, especially Shiguwa growing in Okinawa, etc., and conducted research for the purpose of obtaining a flavourful mulberry tea while minimizing the degradation of DNJ contained therein. As a result, it was found that in order to obtain the desired mulberry tea, the method of the order of basically cooking the shredded mulberry leaves, drying and roasting them was appropriate. Furthermore, as a result of experimentally pursuing the flavor that mulberry tea is excellent as a drink and the conditions capable of preventing the decomposition of DNJ, the present invention was completed.

  That is, the present invention is the production of mulberry tea in which shredded mulberry leaves are cooked, dried and roasted, and the raw mulberry leaves are steamed at a temperature of 80 to 100 ° C. for 1 to 8 minutes. Is a method for producing mulberry tea.

  Moreover, this invention is a manufacturing method of said mulberry tea characterized by performing roasting at the temperature of 80-120 degreeC for 10 to 20 minutes.

  Furthermore, the present invention is the above-mentioned method for producing mulberry tea, characterized in that drying is performed at a temperature of 40 to 80 ° C. for 8 to 16 hours.

  Furthermore, the present invention is the method for producing mulberry tea as described above, wherein the mulberry leaves are shimuwa (Morus australis Poir).

  Furthermore, the present invention provides mulberry green tea and mulberry green tea obtained by the method described above.

  The mulberry tea obtained by the method of the present invention has a very tasty flavor, and DNJ, which is a blood sugar level increase-inhibiting component characteristic of mulberry leaves, is maintained almost as it is. Therefore, by drinking mulberry tea obtained by the method of the present invention, proteins, dietary fibers, physiologically active ingredients, minerals, amino acids, etc. contained in mulberry leaves can be easily ingested. It can be used.

  In addition, mulberry tea obtained by the method of the present invention, especially mulberry tea made from shimuwa, contains abundant DNJ and has an inhibitory action on the increase in blood glucose level. It is a very good beverage.

  The mulberry tea of the present invention is prepared by steaming mulberry leaves cut to an appropriate size, then drying and roasting.

  The mulberry leaves used as a raw material in the present invention are not particularly limited in their varieties, and mulberry leaves of known varieties such as Lotus (Morus lhou) and Yamagus (Morus bombycis) can be used. However, it is preferable to use leaves of Morgus australis Poir from the point that the content of DNJ is extremely high.

  The mulberry leaves that are the raw materials are first washed with water after removing attached foreign substances such as dead leaves by visual inspection. This is then chopped into appropriate sizes. The shredding is preferably in the form of a strip having a width of about 10 mm to 20 mm, for example, parallel to the main veins of mulberry leaves.

  The shredded leaves are then steamed. This steaming is performed in a temperature range of 80 to 100 ° C. for 1 to 8 minutes using an instrument such as a commercially available steamer (two-stage PE steamer, etc.). More preferable conditions for this cooking are 85 to 95 ° C. and 2 to 6 minutes.

  If the cooking temperature is low or the cooking time is short and the cooking is not enough, the enzyme contained in the mulberry leaves will not be inactivated, resulting in a blue odor or a taste. And problems such as a decrease in color. Conversely, when the cooking temperature is too high or the cooking time is too long, the mulberry leaves may have a reddish or steamed odor, which is not preferable.

  Further, the steamed mulberry leaves are dried to remove moisture. Although this drying may be natural drying such as air drying, industrially, mechanical drying using a dryer is preferable. The drying conditions in the case of mechanical drying are a drying temperature of about 40 to 80 ° C., preferably 50 to 70 ° C., and a drying time of about 8 to 16 hours, preferably 10 to 14 hours.

  If the drying temperature is too low or the drying time is short and the drying is inadequate, moisture may remain in the mulberry leaves and cause mold and the like.

  The dried mulberry leaves are roasted. This roasting is performed using a roasting machine such as a commercially available roasting machine (far-infrared food baking machine BAI-SEN or the like) at a temperature of about 80 to 120 ° C., preferably 90 to 110 ° C. It may be performed for about 20 minutes, preferably 12 to 18 minutes.

  When the roasting temperature is low or the roasting time is short and roasting is insufficient, problems such as a decrease in flavor and taste occur. On the other hand, if the roasting temperature is too high or the roasting time is too long, the color and taste will be lowered and a burning odor may be produced, which is not preferable.

  The mulberry tea of the present invention obtained as described above has an average particle size of about 20 to 40 μm as it is or when further measured with a particle size distribution measuring device (laser diffraction type particle size distribution measuring device SALD-2200) or the like. The final product is pulverized until it becomes a fine powder.

  First, when the mulberry tea obtained by the above method (hereinafter sometimes referred to as “mulberry sencha”) is used as it is, the mulberry sencha has a heat of about 60 to 90 ° C., about 100 to 200 times by weight. What is necessary is just to drink water as it is, adding hot water extract obtained. When drunk in the form of this mulberry tea, the sweetness and flavor peculiar to mulberry tea can be tasted and active ingredients such as DNJ exuded from mulberry tea can be ingested.

  On the other hand, mulberry tea obtained by the above method in a fine powder form (hereinafter sometimes referred to as “mulberry matcha”) can be drunk as it is suspended in water, hot water, milk or soy milk. When drinking in the form of this mulberry tea, it is possible to drink all the active ingredients contained in mulberry tea in addition to the active ingredients that exude from mulberry tea, which is extremely effective for maintaining health. Moreover, this mulberry matcha tea can be blended in various foods as a food material in addition to drinking as described above. In particular, it can be advantageously blended in foods rich in carbohydrates.

  EXAMPLES Next, although an Example is given and this invention is demonstrated further, this invention is not restrict | limited at all by these Examples. In the following examples, the average particle size is a value measured by a particle size distribution measuring device (laser diffraction particle size distribution measuring device SALD-2200).

Example 1
Mulberry tea production:
The branches grown to a length of about 1 to 2 m are cut from the mulberry tree of Morus australis Poir cultivated in Urasoe, and the mulberry leaves are picked so as not to be damaged. From the picked mulberry leaves, foreign matters such as dead leaves are visually removed, and the attached dirt is removed by washing with water.

  The mulberry leaves washed as described above are shredded in parallel with the main veins into a strip shape having a width of about 1 cm and steamed. Steaming is carried out in a steamer (PE commercial corner steamer 2nd stage) at a temperature of 90 ° C. for 4 minutes. The steamed chopped mulberry leaves are allowed to cool to room temperature (25 ° C.), then placed in a dryer (electric food dryer TE-10-AD) and dried at a temperature of 60 ° C. for 12 hours.

  The dried mulberry leaves are roasted at a temperature of 100 ° C. for 15 minutes in a roaster (far-infrared food baking machine BAI-SEN) to obtain the present mulberry tea 1. After drying, this product is sealed as it is in a packaging container to obtain mulberry green tea (product 1A of the present invention). Further, the mulberry tea 1 of the present invention is pulverized to an average particle size of about 30 μm using a pulverizer (Tornado Mill TM-25) to obtain mulberry matcha tea (product 1B of the present invention).

Example 2
Except for setting the steaming time in Example 1 to 2 minutes, the same procedure as in Example 1 is carried out to obtain mulberry tea (present product 2A) and mulberry matcha tea (present product 2B).

Example 3
Mulberry Sencha (present product 3A) and Mulberry Matcha (present product 3B) are obtained in the same manner as in Example 1 except that the steaming time in Example 1 is 6 minutes.

Comparative Example 1
In Example 1, except that the roasting temperature is 150 ° C., the same procedure as in Example 1 is performed to obtain mulberry tea (Comparative product 1A) and mulberry matcha tea (Comparative product 1B).

Comparative Example 2
Mulberry tea (Comparative product 2A) and Mulberry matcha tea (Comparative product 2B) are obtained in the same manner as in Example 1 except that the roasting time is 150 ° C. and the roasting time is 30 minutes in Example 1.

Test example 1
Taste sensory test:
About Mulberry Sencha (Invention Products 1A-3A and Comparison Products 1A-2A) and Mulberry Matcha Tea (Invention Products 1B-3B and Comparison Products 1B-2B) prepared in Examples 1-3 and Comparative Examples 1-2 Taste and color were evaluated according to the following criteria by 8 panelists. The results are shown in Table 1.

Evaluation criteria:
Score: Contents
◎: Among 8 panelists, 7 or more evaluated as having good taste and color.
◯: Among 8 panelists, those evaluated by 5 to 6 as having good taste and color.
Δ: Among 8 panelists, 3 to 4 evaluated that taste and color were good.
×: Among 8 panelists, 2 or less evaluated as having good taste and color.

  This result shows that roasting is necessary to obtain mulberry tea with good taste and color, and the taste and color are degraded by roasting for 30 minutes or more or roasting at 150 ° C or higher. It was shown that.

Test example 2
α-Glucosidase inhibitory activity and DNJ content measurement test:
The mulberry green tea obtained in Examples 1 to 3 and Comparative Examples 1 to 2 was treated and ground at 1500 rpm for 60 seconds with a multi-bead shocker (MB755HS Yasui Machine) to obtain a powder. To 100 mg of this powder, 1 mL of 80% ethanol was added and extracted overnight at room temperature. This extract was centrifuged at 10,000 rpm for 30 minutes, and the supernatant was collected to obtain a sample solution.

About this solution, those α-glucosidase inhibitory activities were measured by the following method.
Moreover, about DNJ, the density | concentration in each sample solution was measured by LC-MS method using the calibration curve obtained using the solution prepared by the following method from the said DNJ standard solution. The results are shown in Table 2.

  From this result, it became clear that roasting at 150 ° C. or higher reduces the active ingredient.

[Method for measuring α-glucosidase inhibitory activity]
(1) Preparation of α-glucosidase enzyme solution:
1 g of commercially available rat small intestine acetone powder (I1630-10 SIGMA) was suspended in 10 mL of distilled water, and sonication was performed 3 times for 1 minute while cooling with ice using an ultrasonic crusher (sonifier 250 Branson). This suspension was centrifuged at 10,000 rpm for 15 minutes to collect a centrifugal supernatant, which was stored frozen at -30 ° C. This cryopreserved product was thawed at the time of use and used as an α-glucosidase enzyme solution.

(2) Measurement of α-glucosidase inhibitory activity:
Add 10 μL of 0.5 M maltose to 70 μL of 0.1 M maleate buffer (pH 6.0) and mix. To this, 10 μl of each specimen sample is added and preincubated for 10 minutes at 38 ° C., then 10 μl of enzyme solution is added, and the mixture is allowed to react at 37 ° C. for 1 hour in a thermostatic chamber (CTU-Mini TAITEC). The reaction is stopped by adding 100 μl of 2.0 M maleic acid-Tris-NaOH buffer (pH 7.4).

  The amount of glucose liberated by this reaction was quantified by measuring the absorbance at a wavelength of 550 nm with a glucose plate II (Test Wako) (Wako Pure Chemicals) with a Nicro plate reader. The enzyme inhibition test was repeated three times, and the inhibition rate (%) was calculated by the following formula.

Inhibition rate (%) = [((A−B) − (C−D) / (A−B))] × 100
A: Absorbance of control solution
B: Absorbance of control solution blank
C: Absorbance of sample solution
D: Absorbance of sample solution blank

[Preparation of deoxynojirimycin standard solution]
10 mg of 1-deoxynojirimycin biochemical (Wako) was dissolved in 100% methanol to prepare a 50 mL standard stock solution. This standard stock solution was diluted with 100% methanol to 0.2, 0.5, 1, 2, and 5 μg / mL, respectively, and used as a standard solution.

The mulberry tea obtained in the present invention has a good flavor and flavor such as taste and flavor, and contains many active ingredients of mulberry leaves. Therefore, this beverage can be combined with other food materials to make a functional food as well as a highly-preference beverage.

Claims (8)

After steaming chopped mulberry leaves, dried and a manufacturing mulberry tea roasting it at a temperature of 80 to a steaming Ikuwa leaf 100 ° C., rows that have 1 to 8 minutes, the roasting at a temperature of 80 to 120 ° C., a manufacturing method of mulberry tea, wherein 10 to 20 minutes rows of Ukoto.   The method for producing mulberry tea according to claim 1, wherein drying is performed at a temperature of 40 to 80 ° C for 8 to 16 hours. The method for producing mulberry tea according to claim 1 or 2 , wherein the mulberry leaves are shimuwa (Morus australis Poir). The method for producing mulberry tea according to any one of claims 1 to 3 , wherein the obtained mulberry tea is sencha-like or matcha-like. Mulberry tea obtained by steaming chopped raw mulberry leaves at a temperature of 80 to 100 ° C. for 1 to 8 minutes, then drying and roasting at 80 to 120 ° C. for 10 to 20 minutes . The mulberry tea according to claim 5 , wherein the raw mulberry leaves are shimuwa mulberry leaves. The chopped raw mulberry leaves are steamed at a temperature of 80 to 100 ° C. for 1 to 8 minutes, then dried, roasted at a temperature of 80 to 120 ° C. for 10 to 20 minutes, and then an average particle size of 20 to 40 μm. Mulberry matcha tea obtained by crushing until it becomes. The mulberry matcha tea according to claim 7 , wherein the raw mulberry leaves are shimuwa mulberry leaves.