質構分析 · 流變測試方法 Texture Analysis · Rheological Test Method

蠕變
測試
方法

CREEP
TEST
METHOD

在恆定應力作用下，材料隨時間產生的緩慢形變行為分析。透過 Rapidta 質構分析儀精確量化食品流變特性，揭示材料黏彈性結構。 Analysis of slow material deformation under constant stress over time. Precisely quantify food rheological properties and reveal viscoelastic structure using the Rapidta Texture Analyser.

Creep Test 蠕變柔量Creep Compliance 黏彈性Viscoelasticity 麵團分析Dough Analysis 乳製品Dairy
形變量 / 蠕變柔量 J(t) Deformation / Creep Compliance J(t)
時間 t →Time t →
← 蠕變期 → ← 回復期 → 應力解除 瞬彈 瞬彈回復 永久形變
測試原理Test Principle

什麼是
蠕變測試What Is
Creep Test

蠕變測試（Creep Test）是一種施加恆定應力，觀察材料隨時間變形量的流變學測試方法。測試分為兩個階段：蠕變期（施加應力）與回復期（撤除應力），從而計算材料的黏彈性參數，如即時彈性、延遲彈性及永久黏性流動。

The Creep Test is a rheological method that applies a constant stress and monitors material deformation over time. The test has two phases: the Creep Phase (stress applied) and the Recovery Phase (stress removed), enabling calculation of viscoelastic parameters including instant elasticity, retarded elasticity, and permanent viscous flow.

I
瞬彈形變Instant Elastic Deformation
應力施加瞬間，材料產生即時的彈性形變。此形變完全可逆，撤力後即刻回復，反映材料的彈性模量（E₀）。 Immediate elastic deformation upon stress application. Fully reversible — recovers instantly when stress is removed, reflecting the elastic modulus (E₀).
II
延遲彈性形變Retarded Elastic Deformation
應力持續作用下，材料緩慢累積的延遲形變。撤力後可逐漸回復，體現黏彈性固體的緩慢蠕動行為。 Slow cumulative deformation under sustained stress. Gradually recoverable after stress removal, representing the retarded elastic behaviour of viscoelastic solids.
III
永久黏性流動Permanent Viscous Flow
不可逆的黏性流動形變，撤力後無法回復。此部分反映材料的黏性系數（η），決定產品的流動性與塗佈性。 Irreversible viscous deformation that cannot recover after stress removal. Reflects the viscosity coefficient (η), governing product spreadability and flow.
測試機制Test Mechanism

Burgers
模型解析Burgers
Model Analysis

恆定應力 σ₀Const. Stress σ₀
FOOD SAMPLE
恆定負荷持續作用Constant Load Applied

Burgers 模型由麥克斯韋（Maxwell）元件與開爾文-福格特（Kelvin-Voigt）元件串聯組成，可完整描述食品材料的蠕變行為。

The Burgers model connects a Maxwell element in series with a Kelvin-Voigt element, providing a complete description of creep behaviour in food materials.

蠕變柔量 J(t) 的方程式：Creep compliance J(t) equation:
J(t) = 1/E₀ + 1/E₁(1-e-t/λ) + t/η₀

其中各參數反映材料的不同流變特性，可用於比較不同配方、加工條件或儲存條件對產品質構的影響。 Each parameter reflects a distinct rheological property, enabling comparison of formulations, processing conditions, or storage effects on texture.

E₀
瞬時彈性模量Instant Elastic Modulus
E₁
延遲彈性模量Retarded Elastic Modulus
λ = η₁/E₁
遲滯時間Retardation Time
η₀
黏性係數Viscosity Coefficient
應用案例Application Cases

食品蠕變
測試應用Food Creep
Test Applications

12
食品 · 烘焙食品 · 麵包麵團Food · Bakery · Bread Dough
麵團發酵流變分析Dough Fermentation Rheology
圓柱探頭 · 麵團硬度測試組Cylinder Probe · Dough Firmness Rig
使用圓柱形探頭配合麵團硬度測試組，以恆定應力壓入麵包麵團，測量酵母在不同發酵時間下對麵團黏彈性的影響。蠕變期間記錄麵團軟化程度，回復期分析麵筋網絡的彈性復原能力。
A cylindrical probe with the Dough Firmness Rig applies constant stress into bread dough to measure how yeast activity at different fermentation stages affects dough viscoelasticity. The creep phase records softening; the recovery phase reveals gluten network resilience.
蠕變柔量 J(t)Creep Compliance J(t) 發酵時間Fermentation Time 麵筋彈性Gluten Elasticity 氣泡保留Gas Retention 加工適性Processability
未發酵 發酵後
62
食品 · 乳製品 · 奶油與人造奶油Food · Dairy · Butter & Margarine
人造奶油硬度蠕變分析Margarine Hardness Creep Analysis
45° 錐形 45° 探頭 · 壓克力45° Cone Probe · Acrylic
採用45° 錐形壓克力探頭，模擬傳統針入度計測試方法，對人造奶油樣品施加恆定位移（距離/壓），記錄產品蠕變柔量曲線。適用於評估不同油脂配方、溫度條件下的塗抹性與硬度穩定性。
A 45° acrylic cone probe simulates a traditional penetrometer, applying constant displacement (distance/compression) to margarine. The resulting creep compliance curve evaluates spreadability and hardness stability across fat formulations and temperatures.
針入度對應Penetrometer Equiv. 塗抹硬度Spread Hardness 溫度穩定性Temp. Stability 油脂結晶Fat Crystallisation 配方比較Formulation QC
硬質奶油 軟質奶油
操作流程Operating Workflow

蠕變測試
標準流程Creep Test
Standard Procedure

01
樣品
準備Sample
Prep
02
探頭
選擇Probe
Selection
03
參數
設定Parameter
Setup
04
執行
測試Run
Test
05
數據
分析Data
Analysis
樣品準備Sample Prep
統一樣品形狀與尺寸，控制溫度，確保樣品表面平整，去除氣泡。Standardise sample shape and size, control temperature, ensure a flat surface, and remove air bubbles.
探頭選擇Probe Selection
依材料特性選擇圓柱、錐形或平板探頭，確保探頭面積與樣品匹配。Choose cylinder, cone, or flat-plate probe based on material; ensure probe area matches sample dimensions.
參數設定Parameter Setup
設定目標應力（或位移）、蠕變時間與回復時間，通常各 30–300 秒。Set target stress (or displacement), creep duration and recovery duration — typically 30–300 s each.
執行測試Run Test
儀器自動維持恆定應力，同步記錄時間—形變量曲線與力值數據。The instrument auto-maintains constant stress while logging time–deformation curves and force data simultaneously.
數據分析Data Analysis
匯出蠕變柔量曲線，擬合 Burgers 模型，計算 E₀、E₁、η₀ 等流變參數。Export creep compliance curves, fit the Burgers model, and calculate rheological parameters E₀, E₁, η₀, etc.
測試參數Test Parameters

建議測試
參數設定Recommended
Parameter Settings

參數Parameter 麵包麵團（#12）Bread Dough (#12) 人造奶油（#62）Margarine (#62) 說明Notes
探頭類型Probe Type 圓柱探頭（配麵團測試組）Cylinder Probe (Dough Firmness Rig) 45° 錐形探頭（壓克力）45° Cone Probe (Acrylic) 依樣品材質與測試目的選擇Select by material and test objective
測試模式Test Mode 蠕變（恆定應力）Creep (Constant Stress) 距離-壓（恆定位移）Distance-Compression (Const. Displacement) 蠕變期恆定；回復期撤除Held during creep; removed in recovery
接觸力Contact Force 0.5 – 2.0 g 1.0 – 5.0 g 輕觸定位，避免預壓縮Light contact to avoid pre-compression
目標應力/位移Target Stress/Displacement 1 – 10 g（視發酵程度）1 – 10 g (depending on fermentation) 5 – 20 mm（模擬針入度）5 – 20 mm (simulating penetrometry) 在線性黏彈區域內操作Operate within the linear viscoelastic region
蠕變時間Creep Time 60 – 180 秒60 – 180 s 30 – 120 秒30 – 120 s 觀察形變速率趨於穩定Until deformation rate reaches steady state
回復時間Recovery Time 60 – 180 秒60 – 180 s 30 – 120 秒30 – 120 s 通常與蠕變時間相等Typically equal to creep time
溫度控制Temperature Control 25°C ± 0.5°C 20°C ± 0.5°C 溫度影響流變特性顯著Temperature significantly affects rheology
重複次數Replicates ≥ 5 次≥ 5 ≥ 5 次≥ 5 確保統計可靠性Ensure statistical reliability