Creating a food database using ATR

by

Alejandro Blinder

Sponsored by Dr. M. Salim Diab

What is Attenuated Total Reflectance (ATR) ?

• Single-reflection accessory of the Fourier Transform Infra Red (FT-IR)

• Electromagnetic radiation in the infrared range.

• Energy Beam penetrates the sample and the reflected energy is analyzed

• Spectroscopy: interaction of energy with the sample to perform analysis.

Why is ATR important for the spectroscopy field?

• Advance equipment to analyze samples

• Any sample can be analyze but gases

• Quick method for unknown identification

• Sample is conserved

• Low amount of sample is required

• Computer analyze the samples for you

Libraries in general

• Data base of samples

• Work is still being done

• Some examples: flavors, fragrance, dyes, pigments, drugs, food packaging, food additives, aldehydes, ketones, esters, pesticides, etc.

• Two big companies: Aldrich, S.T. Japan

• Libraries are in big demand• They can be very expensive• Most libraries generated by transmission

(IR) lead to unsatisfactory results– Intensity differences because of

penetration depth– Dispersion– Transmission artifacts

Libraries in general

Research Project

• Two parts:– First: Create a reliable ATR library on Food– Second: Test the boundaries of the library

• First part:– Ten samples where analyzed: white bread,

mushroom, celery, cauliflower, tomato, cucumber, olive, carrot, red pepper, and lettuce

Project set up

Project set up

Data obtained

Data obtained

Data obtained

Data obtained

Reliable data

Problems found

• Inconsistency (pressure)

– Lead to bad data

– Low match ups

• Time consuming

– Each sample was run several times

Low match ups

Problem solved

Problem solved

Problem solved

Problem Solved

Second part

• Data Boundaries were tested

– Blends samples

– Mix samples

• Own make

• Found in the market

• Decent data was obtained

Red pepper blend

Red pepper blend

Tomato Blend

Three Cheese Tomato sauce

Tomato sauce w/pepper (jewel)

Carrot and orange juice (mistic)

Carrot juice (Odwalla)

Tomato and Red pepper Blend

Conclusion• ATR useful tool for the spectroscopy field• ATR libraries are needed

– Use of IR libraries lead to unsatisfactory results

– Only two companies are investing in this field• Research project was good overall

– Reliable data– Decent for mix samples

• For the future– Expand library– Keep testing the boundaries of library

Thank You!

Questions?