Advances in Noninvasive Food Analysis

Muhammad Kashif Iqbal Khan, Muhammad Kashif Iqbal Khan

• Publisher: CRC Press
• Year: 2019
• ISBN:
  9780429998201
• Edition: 1
• Topic: Sciences physiques
• Subtopic: Chimie analytique

To ensure food quality and safety food, professionals need a knowledge of food composition and characteristics. The analysis of food product is required for quality management throughout the developmental process including the raw materials and ingredients, but food analysis adds processing cost for food industry and consumes time for government agencies.

Advances in Noninvasive Food Analysis explores the potential and recent advances in non-invasive food analysis techniques used to ensure food quality and safety. Such cost-reducing and time-saving non-destructive food analysis techniques covered include, Infrared, Raman Spectroscopy, and Nuclear Magnetic Resonance. The book also covers data processing and modelling.

Features:

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• Covers the advent of non-invasive, non-destructive methods of food analysis

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• Presents such techniques as near and mid infrared, Raman Spectroscopy, and Nuclear Magnetic Resonance

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• Describes the growing role of nanotechnology in non-invasive food analysis

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• Includes image analysis and data processing and modelling required to sort out the data

The prime for this book are food professionals working in industry, control authorities and research organizations that ensure food quality and safety as well as libraries of universities with substantial food science programs, food companies and food producers with research and development departments.

Also available in the Contemporary Food Engineering series:

Advances in Food Bioproducts, Fermentation Engineering and Bioprocessing Technologies, edited by Monica Lizeth Chavez Gonzalez, Nagamani Balagurusamy, Christobal N. Aguilar (ISBN 9781138544222)

Advances in Vinegar Production, edited by Argyro Bekatorou (ISBN 9780815365990)

Innovative Technologies in Seafood Processing, edited by Yesim Ozogul (ISBN 9780815366447)

1 Introduction

Abid Aslam Maan and Muhammad Adnan Hafeez

University of Agriculture Faisalabad

CONTENTS

1.1 Introduction

1.2 Spectroscopy

1.2.1 Fourier Transform Infrared Spectroscopy

1.2.2 Fluorescence Spectroscopy

1.2.3 Raman Spectroscopy

1.3 Nuclear Magnetic Resonance

1.4 Hyperspectral Imaging

1.5 Nanosensors

1.6 Electronic Tongue

1.7 Ultrasonication

1.8 Microscopy

References

1.1 Introduction

The consumer expectation and demand for safe and high-quality foods necessitate the inspection of the foods according to the mandatory legislation for food safety. The term “quality” is generally referred to as a multilayered (usually neutral) expression (Butz et al., 2005). There are certain external and internal parameters regarding food quality which need to be fulfilled. Some of these quality parameters can be perceived by the consumer with the aid of senses like smell, taste, touch or color. But there are certain other quality characteristics such as wholesomeness, nutritional value, toxicity and safety which cannot be determined by the consumers. The acceptability of the food items can be increased by providing the consumers with these information. Food industry is required to develop rapid, accurate and objective quality systems to inspect the entire food processing to ensure the safety and quality of food products. Usually food safety and quality are determined by its physical (color, texture, marbling tenderness, etc.), chemical (moisture, fat, protein content, pH, etc.) and biological characteristics (total microbial count). Traditionally, food safety and quality evaluation involves human visual inspection along with certain chemical experiments (Huang et al., 2014). Although human visual inspection is subjective, laborious, time-consuming, tedious and inconsistent, it is still widely used.

Instrumental techniques have successfully replaced the chemical experimental methods in various analytical applications and are recognized as more accurate comparatively. Mass spectrometry (MS) and high-performance liquid chromatography (HPLC) are the most commonly used instrumental techniques. However, these analytical techniques are quite time-consuming, involve lengthy sample preparation methods and are destructive making the food sample unable to recover. For example, Gómez-Alonso et al. (2007) reported that HPLC analysis of wine and wine products to assess the phenolic compounds requires a series of complimentary requirements such as purification through liquid–liquid or solid-phase extraction, use of solvent elution and sometimes an additional (initial) extraction step. All these steps make this procedure lengthy, and most importantly, the food sample cannot be recovered in HPLC analyses, which makes it a destructive technique for food analyses. HPLC has found its applications in drugs, amino acids/proteins, carbohydrates and lipids (Lehotay and Hajšlová, 2002). Gas chromatography (GC) has been reported for the analysis of lipids, drugs, pesticides and carbohydrates. Although gas chromatography and liquid chromatography equipped with mass spectrometer (GCMS and LCMS, respectively) are recent techniques used for the quantification of food samples. However, GCMS and LCMS analyses also require pretreatment of samples along with extraction processes and involve the injection of samples which cannot be recovered after analyses proving these techniques as destructive and invasive (Ono et al., 2003). This has urged the researchers to explore and develop novel noninvasive and nondestructive analytical techniques for evaluation of the quality parameters of foods. Exponential increase in literature regarding noninvasive food analysis has been seen during past few years. This shows that these techniques have become very popular for the direct analysis of food products (Garrigues and de la Guardia, 2013). In addition to being noninvasive and nondestructive, these analytical techniques are rapid, accurate and time-saving. A short description of some of these techniques is given in succeeding paragraphs.

1.2 Spectroscopy

Spectroscopy is the most commonly used noninvasive analytical technique in food analyses. It provides the quantitative and qualitative chemical and physical information about the food material resulting from the interaction of atoms or molecules and electromagnetic radiations. It involves the absorbance and emittance of photons from certain wavelengths depending upon their energy content. Mostly, spectroscopic analyses provide the absorption spectra.

1.2.1 Fourier Transform Infrared Spectroscopy

Fourier transform infrared (FTIR) spectroscopy has been explored to verify the authentication of the food products from adulterants, fraudulent or mislabeling. The basic principle behind the FTIR technique is the production of spectra by measuring the variations in the absorbed IR radiations by the molecules. These variations occur when the molecules absorb energy and undergo mechanical changes (rotational and vibrational). When the IR radiations of specific and narrow frequency ranges are applied to any functional group within a molecule, it shows characteristic IR absorption irrespective of its relationship with the rest of the molecules. As the atoms within the molecule have complex interactions, each involves energy of vibration along with its own vibrational transitions. The surrounding atoms sometimes influence the position of the band in the IR spectrum. So, the identification or differentiation between samples can be carried out by IR spectra. Furthermore, it can also provide information about the quantity of functional groups. The infrared region of the electromagnetic spectrum is divided into three areas: far infrared (FIR) (400–50 cm⁻¹), mid-infrared (MIR) (4,000–400 cm⁻¹) and near-infrared (NIR) (14,000–4,000 cm⁻¹). Combination of FT-MIR and FT-NIR with multivariate statistical methods has been applied for the authenticity of agricultural products, fruit juices, dairy products, edible oils and many other food commodities (Rodriguez-Saona and Allendorf, 2011). The production of NIR bands involves the deviations of complex vibrational motion of chemical bonds from harmonicity. These deviations result in the arising of bands of frequency of fundamental vibrations from transitions over two, three or higher energy levels which leads to the decreased absorption intensity of NIR with increasing energy level (Rodriguez-Saona and Allendorf, 2011). De Girolamo et al. (2009) proved the authenticity of FT-NIR analysis to determine deoxynivalenol (DON) in unprocessed wheat at levels far below the maximum permitted limits set by the European Commission. On the other hand, Carbonaro and Nucara (2010) described that FT-MIR has been proved to be a powerful tool for compositional analysis of food, specifically for the molecular architecture of food proteins where it provides high-quality spectra with very small amount of protein in various environments irrespective of the molecular mass. Moreover, chemometric MID-FTIR method has been developed to quantify the adulteration in minced meat (Meza-Márquez et al., 2010).

Beyond these compositional analyses, recent researches have proved that complex processes such as meat tenderness, dough mixing and curd cutting can be monitored and controlled in situ to produce consistent and high-quality end products. Traditionally, these processes have been controlled by highly skilled craftsman. It has been found that adulteration of ground beef with animal and plant proteins, including pork and lamb muscle tissue, skim milk powder and wheat flour can be detected by NIR with an accuracy of approximately 93%. In the field of agriculture, NIR has been used to classify grain kernels with mutant and recombinant genes which speeds up the plant breeding process. NIR spectra have enabled the scientists to determine tomato firmness and bruising in apple due to the subtle compositional differences in fruit (Bock and Connelly, 2008). Fruits and vegetables reserve unique characteristics among food items as their color, shape, size and composition vary even when harvested at the same time, thus requiring sorting process. NIR spectroscopy can effectively be used noninvasively and nondestructively for the measurements of moisture in fruits and vegetables. Previously, NIR spectroscopy has been used to determine quality parameters, which provides the baseline for the researchers to develop online monitoring and grading systems. An automated fruit sorting machine was reported after the successful determination of sugar contents by NIR spectroscopy in intact peaches and mandarins which started a new era of online NIR in fruit and vegetable processing (Huang et al., 2008). Woolliness, a physical disorder in peaches which occurs due to the inadequate storages, is characterized by the lack of crispiness. Ortíz et al. (2001) determined the wooliness in peaches by using impact response and NIR spectroscopy. Normally, carbohydrate analyses of ground samples are performed by NIR spectroscopy. But dry matter (DM) content and total soluble solids (TSS) of intact thin-skinned fruits are determined by shortwave near-infrared spectroscopy (SWNIRS) because it allows assessment of a greater volume of sample due to the lower water absorptivity. However, application of this technique is limited to the analysis of major constituents such as DM and to the thin-skinned fruits (Subedi and Walsh, 2011).

1.2.2 Fluorescence Spectroscopy

Fluorescence spectroscopy is an analytical technique used extensively in the field of chemistry and biochemistry. Fluorescence, by definition, is the emission of light subsequent to absorption of ultraviolet or visible light of a fluorescent molecule or substructure, called a fluorophore. Thus, the fluorophore absorbs energy in the form of light at a specific wavelength and liberate energy in the form of emission of light at a higher wavelength (Karoui and Blecker, 2011). Fluorescence spectroscopy has found its applications in the identification of meat, fish, edible oils and dairy products. However, freshness of eggs can also be determined by using fluorescence spectroscopy (SádeCká and TóThoVá, 2007).

1.2.3 Raman Spectroscopy

In Raman spectroscopy, a laser beam is directed towards the sample to scatter a small number of photons in the sample. The incident photons and the molecules of the sample collide inelastically resulting in a change in the rotational or vibrational energy of the molecule and thus shifting the scattered radiations to a different wavelength. The difference between the frequencies of incident radiation and scattered radiation is called the Raman shift. Stokes lines in the Raman spectrum arise when the scattered photons are shifted to a longer wavelength due to the energy gaining behavior of the molecule. On the other hand, anti-Stokes lines arise due to the shifting of scattered photons to a shorter wavelength. The obtained spectra present the frequency shifts of scattered light and can be analyzed (Yang and Ying, 2011). FT-Raman spectroscopy proved itself as a valuable tool for the structural analysis of sugar beet and commercial citrus pectin, and more complete characterization of pectin samples was observed by using the combination of FT-Raman and FTIR spectroscopic methods. Furthermore, FT-Raman technique has been employed for the detection of foodborne microorganisms on the whole apple surface, and the results described 100% accuracy for the differentiation of pathogens and non-pathogens (Yang and Ying, 2011).

1.3 Nuclear Magnetic Resonance

Another noninvasive and nondestructive method of food analysis is the use of low-field nuclear magnetic resonance (NMR). It involves the presence of an external static magnetic field to measure the absorption of resonant radio frequency by non-zero nuclear spins. Due to its high reproducibility and sensitivity, it has become a powerful technique in food analysis. NMR technology has been used for the identification of different food samples including beef, corn and honey on the basis of hydrogen proton difference (Geng et al., 2015). In industrial sector, time-domain nuclear magnetic resonance (TD-NMR) is the most popular technology for assessment of food quality and safety. It is also known as a low-resolution or low-field NMR. TD-NMR primarily uses low-cost benchtop spectrometers with permanent magnets. Fourier transform has low-intensity magnetic field, and lacking in the homogeneity of magnetic field does not allow the detection of chemical shift and ultimately limits its application. However, TD-NMR technology relies upon the analyses of the amplitude of the free induction decay and spin-ec...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Dedication Page
• Table of Contents
• Series Preface
• Series Editor
• Preface
• Editor
• Contributors
• Chapter 1 Introduction
• Chapter 2 Near-Infrared Spectroscopy in Food Analysis
• Chapter 3 Mid-Infrared Spectroscopy
• Chapter 4 Vibrational Spectroscopy for Food Analysis
• Chapter 5 Microwaves as Non-Invasive Analytical Tool
• Chapter 6 Ultrasounds
• Chapter 7 Nuclear Magnetic Resonance Spectroscopy: A Useful Analytical Tool to Determine Different Parameters in Food Applications
• Chapter 8 Role of Nanotechnology in Noninvasive Food Analysis
• Chapter 9 Electronic Nose
• Chapter 10 Image Analysis
• Index