A drying color protection process of purple bamboo shoots rich in anthocyanins
By soaking in a compound color-protecting solution of fruits and vegetables and then drying with hot air, the problem of anthocyanin loss during the drying process of purple bamboo shoots was solved, achieving maximum retention of anthocyanins and preservation of sensory quality, thus improving the product's shelf life and market acceptance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN AGRI UNIV
- Filing Date
- 2024-12-19
- Publication Date
- 2026-06-23
AI Technical Summary
Purple thorn bamboo shoots are prone to anthocyanin loss during the drying process, resulting in a decline in sensory quality, low market acceptance, and difficulty in preservation.
Purple thorn bamboo shoots were soaked in a compound fruit and vegetable color-protecting solution and then dried with hot air at 50–70°C until the weight difference was less than 0.02g. They were then vacuum-packed for storage.
It effectively preserves the anthocyanin content and activity in purple thorn bamboo shoots, maintains good sensory quality, solves the preservation problem, and enhances market acceptance.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of food processing technology, and in particular to a drying and color-preserving process for purple thorn bamboo shoots rich in anthocyanins. Background Technology
[0002] Purple thorny bamboo shoots are a type of bamboo shoot native to Ya'an. Visually, the shoots and nodes of purple thorny bamboo shoots have a distinct purple hue, primarily due to their high anthocyanin content. While ordinary bamboo shoots also contain anthocyanins, the amounts are extremely low. Therefore, purple bamboo shoots have higher development and utilization value. Furthermore, purple thorny bamboo shoots grow entirely in the wild, making them prone to spoilage and deterioration under normal conditions after harvesting. They are difficult to store and have a short shelf life, and their anthocyanin content is easily lost. During subsequent cooking and processing, purple thorny bamboo shoots tend to darken or turn black, severely affecting their sensory quality and leading to lower market acceptance, thus hindering the development of the purple thorny bamboo shoot industry.
[0003] In recent years, drying has become a popular bamboo shoot processing method both domestically and internationally for extending the shelf life of bamboo shoots. However, research on the drying of purple thorny bamboo shoots has not yet been reported. Therefore, drying can be used to process purple thorny bamboo shoots into dried bamboo shoots. At the same time, because purple bamboo shoots are rich in anthocyanins, which have complex structures and poor stability, it is necessary to protect these anthocyanins before drying to maximize their content and activity. Summary of the Invention
[0004] This invention provides a drying and color-preserving process for purple thorn bamboo shoots rich in anthocyanins. The optimal temperature for hot air drying of purple thorn bamboo shoots is determined. At this temperature, the good sensory quality of the dried purple thorn bamboo shoots can be well maintained, the color difference before and after drying is small, and the content and activity of anthocyanin substances are preserved to the maximum extent.
[0005] The method includes the following steps:
[0006] Step (1) Select fresh, undamaged purple thorn bamboo shoots, peel off the bamboo shell, wash them with clean water, and then dry the surface with a clean gauze. Cut the bamboo shoots into evenly sized slices, shreds, and strips.
[0007] Step (2) Soak the cut bamboo shoots in the fruit and vegetable color-protecting solution for 1 to 10 minutes, then take them out and place them on a stainless steel baking rack to dry.
[0008] Step (3) After the protective liquid on the surface of the bamboo shoot sample dries, place it at a temperature of 50-70℃ for drying until the difference between the two weighings is less than 0.02g, which is the drying endpoint. After drying, vacuum pack it and store it at room temperature.
[0009] The selected fresh, undamaged purple thorny bamboo shoots are about 25-45cm long.
[0010] The compound color-protecting liquid for fruits and vegetables has a mass concentration of 0.1–3.0% CaCl2, 0.1–3.0% L-cysteine, and 0.01–2.0% vitamin C.
[0011] The selected drying oven is an electric thermostatic forced-air drying oven, model DHG-9245A. The temperature of the drying oven needs to be raised to the specified temperature of 50-70℃ before putting the bamboo shoots in for drying. The drying endpoint is reached when the difference between the two weighings is less than 0.02g.
[0012] The vacuum packaging bag is a self-sealing aluminum foil bag made of RCPP material. After vacuum heat sealing, it is stored at room temperature.
[0013] Beneficial effects:
[0014] This invention discloses a drying and color-preserving process for purple thorn bamboo shoots rich in anthocyanins. The method is simple and overcomes the difficulties of preserving purple thorn bamboo shoots and their poor market acceptance. It determines the optimal temperature for hot air drying of purple thorn bamboo shoots. At this temperature, the sensory quality and nutritional value of purple thorn bamboo shoots can be well preserved, the color difference before and after drying can be minimized, and the content and activity of anthocyanin substances can be preserved to the maximum extent.
[0015] Figure and Table Description
[0016] Figure 1 Physiological morphology and cross-section of fresh purple thorny bamboo shoots (Germinatus Bambusae Sinospinosae).
[0017] Figure 2 Comparison of protected (a) and unprotected (b) samples of purple thorny bamboo shoot slices (Germinatus Bambusae Sinospin osae) after hot air drying.
[0018] Figure 3 Comparison of the color-protected sample (a) and the unprotected sample (b) of purple thorny bamboo shoot strips (Germinatus Bambusae Sinospin osae) after hot air drying.
[0019] Figure 4 Comparison of protected (a) and unprotected (b) samples of purple thorny bamboo shoots (Germinatus Bambusae Sinospin osae) after hot air drying.
[0020] Figure 5To compare the anthocyanin content, flavonoid content, total phenolic content, and color difference value of dried purple thorn bamboo shoots (Germinatus Bambusae Sinospinosae) after treatment with compound color-protecting solution and blank samples. Detailed Implementation
[0021] Unless otherwise specified, the experimental methods and conditions used in the embodiments of this invention are conventional methods. Unless otherwise specified, the reagents or materials used are all from commercial sources. The following embodiments are further illustrations of the invention, but not limitations thereof.
[0022] Implementation Case 1:
[0023] Select fresh, relatively uniform, and undamaged purple thorny bamboo shoots, approximately 25–45 cm in length. Peel off the outer husks, wash away surface impurities, and pat dry with a clean gauze. Cut the bamboo shoots into 3×5 cm slices. Soak the slices in a compound color-protecting solution (0.1–3.0% CaCl2, 0.1–3.0% L-cysteine, and 0.01–2.0% Vitamin C) for 1–10 minutes. Immediately remove the slices and air dry them on a stainless steel drying rack. Dry them in a 50–70℃ electric thermostatic drying oven until the difference between two weighings is less than 0.02 g, indicating the drying endpoint. The vacuum packaging bags are made of RCPP material. After vacuum heat sealing, pack them in self-sealing aluminum foil bags and store at room temperature.
[0024] Implementation Case 2:
[0025] Select fresh, relatively uniform, and undamaged purple thorny bamboo shoots, approximately 25–45 cm in length. Peel off the outer husks, wash away surface impurities, and pat dry with a clean gauze. Cut the bamboo shoots into 0.5 × 17 cm strips. Soak the strips in a compound color-protecting solution (0.1–3.0% CaCl2, 0.1–3.0% L-cysteine, and 0.01–2.0% Vitamin C) for 1–10 minutes. Immediately remove the strips and air dry them on a stainless steel drying rack. Dry them in a 50–70℃ electric thermostatic drying oven until the difference between two weighings is less than 0.02 g, indicating the drying endpoint. The vacuum packaging bags are made of RCPP material. After vacuum heat sealing, pack them in self-sealing aluminum foil bags and store at room temperature.
[0026] Implementation Case 3:
[0027] Select fresh, relatively uniform, and undamaged purple thorny bamboo shoots, approximately 25–45 cm in length. Peel off the outer husks, wash away surface impurities, and pat dry with a clean gauze. Cut the bamboo shoots into 2×17 cm strips. Soak the strips in a compound color-protecting solution (0.1–3.0% CaCl2, 0.1–3.0% L-cysteine, and 0.01–2.0% Vitamin C) for 1–10 minutes. Immediately remove the strips and air dry them on a stainless steel drying rack. Dry them in a 50–70℃ electric thermostatic drying oven until the difference between two weighings is less than 0.02 g, indicating the drying endpoint. The vacuum packaging bags are made of RCPP material. After vacuum heat sealing, pack them in self-sealing aluminum foil bags and store at room temperature.
Claims
1. A drying and color-protecting process for purple thorny bamboo shoots rich in anthocyanins, characterized in that, The method includes the following steps. Step (1) Select fresh, undamaged purple thorn bamboo shoots, peel off the bamboo shell, dry them, and cut the bamboo shoots into evenly sized slices, shreds, and strips. Step (2) Soak bamboo shoots of different shapes in a fruit and vegetable compound color-protecting solution for 1 to 10 minutes, then remove them and place them on a stainless steel baking rack to dry. Step (3) After the protective liquid on the surface of the bamboo shoot sample dries, place it at a temperature of 50-70℃ for drying until the difference between the two weighings is less than 0.02g, which is the drying endpoint. After drying, vacuum pack it and store it at room temperature.
2. The method according to claim 1, characterized in that, The selected fresh, undamaged purple thorny bamboo shoots are about 25-45cm long.
3. The method according to claim 1, characterized in that, The color-protecting solution has a mass concentration of 0.1–3.0% CaCl2, 0.1–3.0% L-cysteine, and 0.01–2.0% vitamin C.
4. The method according to claim 1, characterized in that, The selected drying oven is an electric thermostatic forced-air drying oven. The temperature of the drying oven must be raised to the specified temperature before the bamboo shoots are put in for drying.
5. The method according to claim 1, characterized in that, The vacuum packaging bag is a self-sealing aluminum foil bag made of RCPP material. After vacuum heat sealing, it is stored at room temperature.