digital image analysis aided Adulteration Detection Data Set for turmeric powder adulterated with flour

Adulteration Detection of Turmeric Powder with Wheat Flour

1. About Turmeric Powder

Turmeric powder (Curcuma longa L.) is a widely used spice known for its flavor, color, and medicinal properties. It contains:

Dietary fiber

Vitamins: C, B6, K

Minerals: iron, potassium, manganese

Bioactive compound: curcumin, responsible for its yellow color and health-promoting effects

2. Adulteration Issue

Common adulterant: Wheat flour

Impact: Reduces purity, dilutes curcumin content, and lowers nutritional value. May also cause digestive issues in gluten-sensitive individuals.

Challenge: Adulterated turmeric powder appears similar to pure turmeric powder; visual detection is difficult.

---

3. Detection Methodology

3.1 Dataset Creation

Samples: Pure and adulterated turmeric powder with wheat flour at varying proportions.

Labeling: Conducted by experts for ground truth reference.

3.2 Image Preprocessing

Grayscale conversion

RGB and HSV analysis

Median smoothing

Adaptive thresholding

Edge detection

These enhance subtle differences between pure turmeric and adulterated samples.

3.3 Feature Extraction

Texture: Smoothness variations due to fine flour particles

Color: Wheat flour lightens the natural yellow hue of turmeric

Surface patterns: Subtle granule distribution changes

---

4. Sample Preparation

Turmeric rhizomes: Collected from Maliha, Malda, West Bengal, India

Moisture content after drying: 4–5% (dry weight basis)

Ash content of turmeric powder: typically ranges from 5–8%

Grinding: Mixer grinder (500 W, 0.5 L jar, hybrid motor, 18,000 rpm, 9 min total → 3 × 3 min cycles)

Sieving: Passed through 60-mesh sieve → undersized fraction used as pure turmeric powder

Wheat flour (adulterant): Collected from a local mill

Cleaned and oven-dried at 50 °C for 4 h

Passed through a 60-mesh sieve for uniform particle size

Mixtures prepared:

0% (pure turmeric), 5%,10%,15%, 20%, 25%,30%,35%, 40%, 45%,50%, and 100% wheat flour by weight

---

5. Image Acquisition

Sample setup:

24sets of samples prepared:

Pure turmeric (100%)

Pure wheat flour (100%)

Adulterated turmeric samples (5–50% wheat flour by weight, at 10% intervals)

White A4 sheet (210 × 297 mm, 80 gsm) divided into 20 equal cells

Thin layer of sample spread evenly in each cell

Total images: 24 × 20 = 480 images

Camera specifications:

Device: Redmi 12 5G smartphone

OS: Android 12

Processor: Octa-core MediaTek Helio P35

Camera:

Rear: 50 MP f/1.8 (wide), 2 MP f/2.4 (depth)

Front: 8 MP f/2.0

Sensor size: 1/3.06", 1.12 µm

Lighting: Natural, no flash
Lens-to-sample distance: 15 cm