JPS6243657B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing onions having a preferable roasted flavor and a mellow sweetness. This is a method for producing onions with a roasted flavor, which comprises heat-treating the onions again using a drum dryer set at a temperature range of 105 to 170°C. Onions are an indispensable vegetable for all kinds of dishes, including eating them raw (salads, etc.), frying, boiling, boiling, soups, etc. However, because of the pungent odor and bitterness characteristic of green onions, they are usually cooked unless they are eaten raw. do enough,
The pungent odor and bitterness are removed, and the sweetness is brought out before it is eaten. The phenomenon in which the pungent odor and bitter taste of onions disappear due to heat treatment is due to the fact that the stimulating component, allyl sulfide, is vaporized by the heat, and a portion of it is further decomposed and converted into propyl-mercaptan, the sweet component. It is generally said that. Frying onions in oil before using them in curry, stew, etc. is a heat treatment that eliminates the pungent odor and bitterness, develops sweetness, and imparts a roasted odor, thereby further improving the flavor of the dish. It is said that this is for the purpose of In order to obtain roasted onions with a desirable roasted flavor, the heating temperature must be at least
It is necessary to heat the onions sufficiently and uniformly at 100℃ or higher to perform the roasting process.When roasting a relatively small amount of onions at home, restaurant, etc., simple heating and stirring is required. It is sufficient to simply add additional operation, but when using large-scale industrial equipment such as a direct-fired flat pot, stirring operations are generally insufficient, resulting in uneven heating and partially burnt parts. It has been difficult to obtain high-quality roasted onions because of variations in quality due to the occurrence of odor and residual fishy odor. Especially when it is necessary to process a large amount of onions at once, the water in the onions (onions usually contain about 90% water) gradually oozes out, and as a result, over time, the oil in the oil system becomes The heating process (roasting process) shifts to heating process (stewing) in a water system, and it is not possible to perform a satisfactory roasting process at high temperatures, so even if sweetness is expressed, it is not roasted flavor. No treated onions were obtained. The roasted flavor of onions developed through the roasting process contributes to enhancing the flavor of various dishes, especially Western-style dishes.
In addition, since its use is wide-ranging, such as enhancing the palatability of various instant foods, there is a desire in the food industry for efficient bulk production of roasted onions with excellent quality. However, due to the problems mentioned above,
Currently, the amount of onions processed at one time is usually kept to a relatively small amount using a small kneader, and the onions are repeatedly roasted. In view of the above-mentioned current situation, the present inventors have conducted various studies in order to industrially advantageously produce onions with a desirable roasted flavor and mellow sweetness.
It has been discovered that by employing a dual heating method of preheating and heating at a specific temperature using a drum dryer, desired processed onions can be obtained without using conventional roasting methods. The present invention was completed based on the fact that the inventors conducted further research, and that is, the peeled raw material onions are subjected to a drum dryer treatment, which is a secondary heating process, to finally achieve a sufficient sweetness. Perform a preliminary heat treatment at a temperature of 60°C or higher to achieve the desired effect.
Furthermore, a grinding process is performed before or after preheating. Heating with a drum dryer is done by setting the surface temperature of the dryer to 105-170℃.
The synergistic effect of both heating processes made it possible to impart a desirable roasted flavor and mellow sweetness to the onions. In this way, the present invention preheats onions, a vegetable with a special structure and components, at 60°C, grinds them before or after that, and then heats them as secondary heating using a drum dryer, which is the most suitable for such material processing. is applied, and the surface temperature of the dryer is
By setting the temperature to 105 to 170°C, it was possible to industrially most efficiently produce for the first time onions with roasted flavor and sweetness in a flaky or easily powdered state as described below. The method of implementing the present invention will be explained in detail below. In the present invention, it is possible to perform preheating treatment and grinding treatment on peeled and washed raw onions in an appropriate order, but it is better to perform preheating treatment first in terms of taste, aroma, and palatability. It is preferable. This is because the off-taste producing substances (presumed to be mainly enzymes) that convert off-taste substances contained within the onion cells into off-taste substances are inactivated by the preheating process, and the subsequent grinding process deactivates them. This is because even if cells are destroyed and foreign taste substances leak out of the cells, it is thought that they will not be converted into foreign taste substances. However, even if the grinding treatment is performed before the preheating treatment, it is still superior to the conventional one-stage heating method. If the onions are cut into pieces or sliced into 2-3 mm thick pieces before heating, the onion cells will hardly be destroyed by this level of processing, so the heat will be applied evenly, resulting in more efficient heating. Can be processed. As for the heating method, normal methods such as boiling, (adding water if the amount to be processed is small) or frying with steaming oil can be used, but whatever treatment method is used, the heating temperature must be 60℃ or higher. I need.
At temperatures below 60°C, as is clear from the comparative examples below, even if the onions are heated for a long time, the sweetness of the onions cannot be fully expressed and a fishy odor remains. Therefore, processed onions with satisfactory flavor cannot be obtained. Only when the heating temperature is set to 60°C or higher can a synergistic effect with the drum dryer treatment be expected, and the sweetness of the onions can be fully brought out. However, 100
When performing preheating treatment at a high temperature of .degree. C. or higher, it is necessary to add stirring operations from time to time to prevent the treated onions from burning, and although the treatment time is shortened to some extent, the work is complicated. Therefore, for processing conditions in this step, mainly for operational reasons, it is preferable to heat the onion at a temperature of 70 to 100°C until it becomes soft and transparent, that is, heating for about 30 minutes. The palatability of the final product can be further improved by adding an appropriate amount of edible fats and oils such as lard and salad oil or monosaccharides such as glucose, fructose and xylose during preheating. It is also believed that the addition of these oils and fats helps to uniformly and efficiently perform the drum dryer heat treatment. Various methods can be suitably employed as the method for grinding onions in the present invention. For example, the degree of grinding, such as crushing with a mixer, is sufficient as long as it does not interfere with drum dryer processing, that is, it is in the form of a puree or a paste. Various starches such as cornstarch, boiled potatoes, etc. may be appropriately mixed as a binder and the grinding process may be carried out at the same time. In this way, it is possible to reduce adhesion to the scraper (scraping blade) during treatment with a drum dryer, thereby improving mechanical suitability, and it is also convenient to handle the product after the treatment. The onion paste that has been subjected to the above preliminary heating treatment and grinding treatment is applied in the form of a film onto the surface of a heated rotating drum via a feeder, and the heating treatment is performed while the drum is rotating. In this process, the surface temperature of the drum dryer is set to 105
It is necessary to set the temperature to ~170℃. If the surface temperature is 105° C. or lower, the main heat treatment is no more than a mere drying treatment, and the treated onions having the roasted flavor of the present invention cannot be obtained. Furthermore, if the surface temperature exceeds 170°C, scorching cannot be avoided even if the drum rotation speed is increased and the processing time is shortened as much as possible, and there are also equipment problems such as the need for a drum that can withstand high pressure. be. The heat treatment time can be determined as appropriate in consideration of the color, aroma, physical properties, etc. of the product onion, but a preferable range is about 180 to 5 seconds, corresponding to a drum surface temperature of 105 to 170°C. Processed onions are heat-treated with a drum dryer and scraped off with a scraper, and have an appetizing roasted flavor and a mellow sweetness.
Its appearance is a golden-brown film. Immediately after production, the sugar in the onion is eluted by heating, making it sticky, but if you leave it for a few minutes, the sugar will cool and solidify again, making it extremely easy to crush into flakes using a regular crusher or by hand. A solid or powdered product is obtained. In addition, the onions processed according to the present invention have a fractional distillation rate of about 10% compared to raw onions, excluding additives such as fats and sugars, due to the two-time heat treatment, making them bulkier compared to conventional roasted onions. First, since the onions are well dried (the conventional fractionation of roasted onions is usually about 30 to 50%), they are very easy to handle during transportation, storage, packaging, etc. The onions treated according to the present invention are quickly suspended or dissolved in an aqueous solution by a simple stirring operation, and therefore have extremely good suitability for secondary processing as raw materials for curry roux, stew roux, and various snack foods. Furthermore, unlike conventional onion powder (described in detail in the comparative experiment examples below), chopped onions, minced onions, etc., the treated onions of the present invention can be eaten as is, making them suitable for snacks for infants and snacks for drinks. It is. Comparative experimental examples are given below to demonstrate the significance of each treatment step and each treatment condition, which are the characteristics of the method of the present invention. Comparative Example Experimental Example Samples A to H were prepared by the method shown below, and their color, aroma, and taste were measured and compared. Sample (product of the present invention): A raw onion that has been peeled and washed with water is cut into pieces with a thickness of about 2 mm using a slicer. Add the same amount of water and 4% lard to the onion, and boil for 30 minutes at a temperature of 90℃. Put the boiled onions into a mixer and crush them for about 20 seconds to make a paste, then raise the surface temperature to 120℃.
Sample A was obtained by heat treatment for 40 seconds using a drum dryer set to . Sample B (product of the present invention): Peeled and washed raw onions were put into a mixer, crushed for about 20 seconds to form a paste, and then the same amount of water and 4% oil to the paste were added. Sample A below
Sample B was obtained by subjecting it to boiling and drum dryer treatment under the same treatment conditions. Sample C: Peeled and washed raw onions were put into a mixer, crushed for about 20 seconds to form a paste, and then treated with a drum dryer under the same processing conditions as Sample A to obtain Sample C. Sample D; processing conditions during boiling: heating temperature 50℃;
Sample D was obtained by performing the same treatment as Sample A except for 60 minutes. Sample E; processing conditions during boiling: heating temperature 50℃;
Sample E was obtained in the same manner as Sample A, except that the sample was heated for 60 minutes and then heated for 10 seconds using a drum dryer with a surface temperature of 173°C. Sample F: A sample was obtained in the same manner as Sample A, except that heat treatment was performed for 4 minutes using a drum dryer with a surface temperature of 100°C. Sample G: Sample G was obtained in the same manner as Sample A, except that heat treatment was performed for 4 seconds using a drum dryer with a surface temperature of 173°C. Sample H (regular onion powder); peeled,
Washed raw onions with a slicer to approx. 2mm
Cut into pieces to a thickness of . This was dried with hot air at about 110°C for 7 hours, and then pulverized using a pulverizer to obtain Sample H. Aroma, taste, and other properties are measured by the senses, and colors are measured by the color difference meter (Nippon Denshoku Kogyo K.K.).
The L value was measured using K.ND-A1). The results are shown in Table-1.

【table】

[Table] As is clear from the above results, in order to obtain onions with a desirable roasted flavor and mellow sweetness, preheating treatment at a heating temperature of 60°C or higher and a drum dryer with a surface temperature set at 105 to 170°C are necessary. However, if either treatment step is missing, or if the treatment conditions deviate from the scope of the present invention, treated onions having the effects of the present invention cannot be obtained. It turns out there isn't. Furthermore, the onions treated by the method of the present invention (samples A and B) had a significant difference in palatability compared to conventional onion powder. As detailed above, according to the method of the present invention, high-quality processed onions with a desirable roast flavor and mellow sweetness can be produced efficiently and industrially without using the conventionally complicated roasting method. This made it possible to manufacture large quantities with great advantage. Example 1 1 kg of peeled and washed raw onions was cut into pieces about 2 mm thick using a slicer. Add 1 water to this,
Add 40g of lard and 20g of glucose, and heat at 80℃.
Simmer for 40 minutes. Add 100g of cornstarch as a binder after adding the boiled onions to the blender.
Add and crush for about 20 seconds to make onion paste. Next, the onion paste was put into a feeder and heat-treated for 30 seconds using a drum dryer whose surface temperature was set to 125°C to obtain treated onions with a desirable roasted flavor. Example 2 1 kg of peeled and washed raw onions was put into a mixer and crushed for about 20 seconds to form a paste, then 200 g of butter and 3 g of xylose were added to it and heated in an open flame pot with appropriate stirring. Do this. The treatment conditions were a heating temperature of 120°C and a duration of 15 minutes. Next, the onion paste was put into a feeder and heated for 50 seconds using a drum dryer with a surface temperature of 115° C. to obtain treated onions with a desirable roasted flavor.

Claims (1)

[Claims] 1. Preheating the onions at a temperature of 60°C or higher, grinding them before or after the heating treatment, and then heating them again using a drum dryer with the surface temperature of the drum set at 105°C to 170°C. A method for producing onions having a characteristic roasted flavor.