Assessing the Potential of NIR Spectroscopy to Determine Fatty Acid Content: An Interview with Daniel Cozzolino

Black soldier fly larvae (BSFL) are often reared on various commercial waste streams. These larvae efficiently convert a wide variety of organic waste, including food scraps, agricultural residues, and by-products from industries, into valuable biomass rich in protein (30–50%), lipids (15–49%), and essential micronutrients (1). By integrating BSFL into commercial waste management systems, industries can not only mitigate environmental impact but also generate economically viable by-products, promoting a sustainable and resource-efficient approach (1).

Daniel Cozzolino is a Principal Research Fellow at the Queensland Alliance for Agriculture and Food Innovation (QAAFI) at the University of Queensland. He has held numerous positions over his career, which include as an Associate Professor in Food Chemistry at RMIT University, Melbourne, the Head of Agriculture at CQUniversity, Rockhampton and a Senior Research Fellow in the Barley Breeding Program at the University of Adelaide (2).

Dr. Cozzolino's research focuses on applying chemometric, machine learning, and spectroscopic techniques (for example, near-infrared (NIR), mid-infrared (MIR), and hyperspectral imaging (HSI)) across various domains, including food, waste products, and agricultural commodities. In one of his most recent studies, he used NIR spectroscopy to analyze BSFL to monitor its fatty acid profiles.

Daniel Cozzolino is a Principal Research Fellow at the Queensland Alliance for Agriculture and Food Innovation (QAAFI) at the University of Queensland | Photo Credit: © Daniel Cozzolino.

Spectroscopy recently sat down with Cozzolino to talk about his research using NIR spectroscopy for BSFL analysis.

Could you elaborate on the significance of black soldier fly larvae (BSFL) in waste stream management and their potential applications in various industries?

It is important to highlight that food waste contributes with more than 5% of the total anthropogenic greenhouse gas emissions. The so-called food waste is arising from different sources including waste from households, restaurants, supermarkets, and other tertiary processing waste sites. Generally, this waste comprised of a diverse set of organic fractions, and it is rich in various macro- and micronutrients. Insects have been considered as an alternative to landfill because they can digest or process a wide range of food waste materials. In this context, BSFL has been utilized to process different types of waste worldwide. The resulting larvae that have been feed with this organic waste has high levels of protein (30-50%), fat (15-49%), fiber (20.4-30.5%), and other micronutrients. More importantly, the amino acid and fatty acid contents of BSFL are considered well balanced and are like those found in fish and soybean meals that are prevalently used as ingredients in feedstuff for livestock. Consequently, BSFL is considered an ingredient of high nutritional value and is a sustainable alternative protein source for livestock. This larva has been used as ingredient in feeds in several regions across the globe. The utilization of multi-stream food waste as a substrate for rearing BSFL has become increasingly popular in commercial production facilities owing to the saprophagous nature of the larvae. It is important to note that the nutritional attributes of such multi-stream food waste vary with demographics, seasonal changes, and other underlying factors (for example, the human diet). Therefore, the nutritional quality of the BSFL reared on such waste streams varies significantly where factors including rearing conditions, physiological age of the harvested larvae, and post-harvest treatments employed could influence it. An important characteristic of the BSFL is that can eat up to five times its weight preventing food waste to go to landfill. This characteristic allows to close the loop in the circular economy transforming tertiary food waste sources that cannot be used directly into a high value ingredient that is utilized back into the food chain. It is also important to highlight that, other products and sub-products derived from the BSFL such as oils, lipids, or chitin have been evaluated and used as ingredients in the cosmetics and pharmaceutical industries.

What motivated you to focus on evaluating fatty acids in BSFL, and how does this research contribute to improving the management and utilization of organic waste streams?

In recent years, NIR spectroscopy, MIR spectroscopy, and HSI have been reported to predict the composition as well as the concentration of individual fatty acids in different insects (for example, Tenebrio molitor larvae). However, no reports on the utilization of NIR spectroscopy to predict individual fatty acids in BSFL collected from commercial waste streams were found in the scientific literature. It is well known that the different waste streams used to feed the larvae modify the concentration and profile of fatty acids in BSFL. For example, lauric acid (C12:0) is considered the most abundant fatty acid in BSFL. Experimental results suggested that lauric acid (C12:0) accumulates as the BSFL gain weight and increases in the later physiological stages of the larvae (for example, instar). Other fatty acids, such as palmitic, appeared in high concentration in the BSFL; however, its concentration or profile depends on the type of waste used to feed the larvae.Therefore, the utilization and implementation of NIR spectroscopy by the industry will enable to monitor the chemical composition of these type of compounds in BSFL.

Why was near-infrared (NIR) spectroscopy chosen as the analytical tool for this study, and what advantages does it offer compared to traditional methods of fatty acid analysis?

The utilization of vibrational spectroscopy, in particular MIR and NIR spectroscopy with their intrinsic benefits such as being non-invasive and rapid, with nearly no necessary sample preparation and an ability to perform on- and inline measurements, have been reported to measure or predict a wide range of physical and chemical parameters in an extensive variety of food ingredients, products, and agricultural products. These advantages were considered and discussed with the industry partner to develop the application discussed in this article (1).

What sample preparation method(s) were most successful for BSFL?

It is well known that sample preparation and presentation to the instrument is a key step in developing an application using NIR spectroscopy. In this study, we have evaluated the whole or parts of the larvae as it is the commonly handled by the industry. However, our team as well as other researchers have reported the use of ground samples.

Could you explain the role of partial least squares (PLS) regression in your calibration models and how it contributed to the accuracy of fatty acid predictions? What spectral data preprocessing methods were most successful for prediction models?

We have used PLS to develop the calibration models and second derivative as preprocessing method.

What were the primary challenges in developing robust calibration models for fatty acids in BSFL?

We faced with different challenges as we have collected samples directly from an industrial site. Challenges included the definition of the sampling strategy, the number of samples to be collected, and the cost of the reference method to analyze the fatty acids. The type of waste showed to have a huge influence on the composition of the larvae, determining a wide variability in the sample and consequently the calibration models. Under industrial conditions, it is challenging to ensure that all the larvae have been seeded with the same amount and type of waste and at the same biological stage.Therefore, the chemical composition of the larvae varied notably with age, having a direct effect on the calibration models.

The best cross-validation model was obtained for palmitic acid. Could you discuss why this fatty acid showed better prediction performance compared to others?

Palmitic acid was the fatty acid with the highest concentration in the set of BSFL samples analyzed because of the type of waste utilized to feed the larvae.

How do you envision NIR spectroscopy being integrated into the production and quality control systems of BSFL at a commercial scale?

The industry is now implementing the utilization of rapid methods not only to determine the chemical composition of the BSFL as ingredients, but they are also improving traceability by monitoring different steps during the process of production. The BSFL is considered a key component in the circular economy, where waste can be minimized and byproducts are repurposed in the form of alternative sources or protein. As NIR spectroscopy enables the identification of compounds as well as provide with a tool to trace the production of this type of ingredients, this will allow the industry to extract valuable ingredients for use in other industries, such as pharmaceuticals and cosmetics. Additionally, the incorporation of NIR spectroscopy ensured that BSFL are utilized efficiently and safe, improving the sustainability of the waste-based production systems. Beyond the prediction of composition, NIR spectroscopy contributes with information that can be incorporated to improve the current management systems during the production and utilization of this type of ingredients. The utilization of NIR spectroscopy allows for the implementation of efficient traceability systems or process analytical systems.

Based on your findings, what are the next steps in advancing the use of NIR spectroscopy for BSFL analysis, and are there other components beyond fatty acids that you plan to investigate?

We have investigated and reported the use of NIR and MIR spectroscopy in a wide range of applications including the prediction of proximate composition (for example, protein, fat, or carbohydrates) in BSFL larvae, monitoring the larvae process and thermal treatment such as drying and blanching, as tool in the traceability of the production system or waste used to feed the larvae, and more recently in monitoring the presence of mycotoxins and the microbiological safety of the larvae. Furthermore, the ability of IR spectroscopy to monitor the occurrence of microplastics in the larvae and frass, or the prediction of frass composition are being evaluated by our team in collaboration with the industry partner. Finally, I would like to thank our industry partner Olympia Yarger from Goterra, and my colleagues Dr. Alagappan and Prof. Hoffman.

References

1. Alagappan, S.; Hoffman, L.; Yarger, O.; Cozzolino, D. A Feasibility Study on the Use of Near Infrared Spectroscopy to Predict Fatty Acid Concentration in Intact Black Soldier Fly Reared in Different Waste Streams. Spectrochimica Acta Part A: Mol. Biomol. Spectrosc. 2025, 330, 125628. DOI: 10.1016/j.saa.2024.125628
2. The University of Queensland, Daniel Cozzolino. University of Queensland. Available at: https://about.uq.edu.au/experts/25408 (accessed 2025-01-16).