溫度對胡蘿卜拉伸彈性模量的影響

楊佳

摘 要：存儲環境的溫度波動對果蔬的力學性能具有重要影響。本文以胡蘿卜為研究對象，利用數字圖像相關（Digital Image Correlation，DIC）方法，測試了胡蘿卜啞鈴試樣的拉伸彈性模量，探究了在不同溫度條件下胡蘿卜彈性模量的變化規律。結果表明，溫度從0 ℃下降到-20 ℃的過程中，胡蘿卜的彈性模量隨著溫度降低呈增大趨勢，當溫度繼續下降到-25 ℃的過程中，胡蘿卜的彈性模量急劇減小;溫度從0 ℃升高到

20 ℃的過程中，胡蘿卜的彈性模量隨著溫度的升高而增大，當溫度繼續升到25 ℃的過程中，胡蘿卜的彈性模量急劇減小，當溫度從25 ℃升高到30 ℃的過程中，其彈性模量又出現微幅上升。該研究表明，通過DIC方法可以探究果蔬在存儲環境出現溫度變化時對其力學性能的影響。

關鍵詞：數字圖像相關;溫度;彈性模量;胡蘿卜

Effect of Temperature on Tensile Elastic Modulus of Carrot

YANG Jia

（School of Mechanical Engineering， Tianjin University of Commerce， Tianjin 300134， China）

Abstract： Temperature fluctuation in storage environment has an important effect on the mechanical properties of fruits and vegetables. Taking carrot as the research object， this paper tested the tensile elastic modulus of carrot dumbbell sample based on the digital image correlation method， and explored the change rule of the elastic modulus of carrot under different temperature conditions. The results showed that when the temperature dropped from 0 ℃ to -20 ℃， the elastic modulus of carrots increased with the decrease of the temperature. When the temperature continued to drop to -25 ℃， the elastic modulus of carrots decreased sharply. In the process of temperature rising from 0 ℃ to 20 ℃， the elastic modulus of carrot increased with the increase of temperature. When the temperature continued to rise to 25 ℃， the elastic modulus of carrot decreased sharply. When the temperature continued to rise from 25 ℃ to 30 ℃， the elastic modulus of carrot increased slightly. This study indicated that DIC method can be used to explore the influence of fruits and vegetables on their mechanical properties when temperature changes occured in the storage environment.

Keywords： digital image correlation; temperature; elastic modulus; carrot

胡蘿卜因含有豐富的營養價值而被越來越多的人所喜愛。果蔬受貯藏時間和環境溫度的影響，其品質和質地會發生變化[1-2]。傳統的低溫（4 ℃左右）儲運有利于保持胡蘿卜的品質，而較高溫度（20 ℃左右）的短期儲運不僅能保證新鮮胡蘿卜的安全性和品質，還能提高胡蘿卜的抗氧化活性和營養價值[3]。彈性模量是評價果蔬力學性能的重要指標，研究溫度對彈性模量的影響，以及如何實現果蔬力學性質的快速測量，能為果蔬存儲運輸以及生物力學性質研究等方面提供重要的技術支持[3-5]。

目前測量果蔬的彈性模量主要是接觸式測量。吳亞麗等[6]用壓痕法測定果蔬的彈性模量，建立了彈性模量與壓痕變形的數學模型。……