**2. Overview of the role of moisture, drying temperature, and extraction technology in polyphenol extraction from food sources**

The presence of numerous phenolic groups distinguishes polyphenols, a general family of secondary metabolites found in plants. Flavonoids (flavones, flavonols, flavanones, etc.), phenolic acids (hydroxybenzoic acids, hydroxycinnamic acids), stilbenes, lignans, and tannins are some of the subclasses into which these chemicals are divided (**Figure 1**). According to Perino-Issartier et al. [10], each subclass has distinct biological and chemical characteristics. The Importance of Polyphenols in the Improvement of Food Lipid Quality Polyphenols have been thoroughly investigated for ability to improve food lipid quality. They have exceptional antioxidant qualities that can prevent lipid oxidation, which is the main factor in the rancidity and degeneration of lipid-based foods. Lipid oxidation causes sensory alterations, such as off flavours and colour deterioration,

*Polyphenol Extraction for the Enhancement of Food Lipid Quality, with an Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.112946*

**Figure 1.** *Plant polyphenol classification (source: Golmakani et al. [9]).*

as well as the loss of vitamins and important fatty acids, which lowers the food's nutritional value [11]. In order to successfully prevent oxidative damage and increase the shelf life of foods containing lipids, polyphenols work as free radical scavengers, chelators of pro-oxidant metal ions, and regulators of lipid peroxidation [12].

### **2.1 Moisture and polyphenol extraction**

The amount of moisture in raw materials has a big influence on how well polyphenols are extracted. Water can make polyphenols more soluble, facilitating release from the food matrix during extraction. However, too much moisture can also cause enzymatic and non-enzymatic processes that cause polyphenols to degrade and disappear. In order to maximise the yield of polyphenol extraction and maintain the quality of the end product, moisture content must be well controlled [13].

Drying Temperature and Polyphenol Extraction: Another important factor that affects polyphenol extraction is drying temperature. By making polyphenols more solubilised and diffusible, higher temperatures can quicken the extraction process. However, too much heat can also result in bioactivity loss and thermal deterioration. In order to maximise polyphenol extraction efficiency while maintaining veracity, it is crucial to determine the ideal drying temperature [6, 7].

#### **2.2 Polyphenol extraction and extraction technology**

To effectively recover polyphenols from dietary sources, a variety of extraction processes are used. Common techniques include solvent extraction, solid-phase extraction, and supercritical fluid extraction (**Figure 2**). Solid-phase extraction

#### **Figure 2.**

*Polyphenol extraction techniques and methods (source Sridhar et al. [14]).*

makes use of solid adsorbents to selectively capture target chemicals, whereas solvent extraction uses organic solvents to extract polyphenols.

Polyphenols are extracted using supercritical fluids, such as carbon dioxide, under carefully regulated circumstances. The extraction yield, selectivity, and costeffectiveness are all impacted by the benefits and limits of each approach [5, 15, 16]. The antioxidant abilities, how they affect sensory qualities, and how they can make lipid-based foods last longer on store shelves. How moisture content and drying temperature affect the effectiveness of polyphenol extraction and the preservation of bioactivity. For the [17] extraction process to be optimised and the full potential of polyphenols to enhance food lipid quality to be realised, it is essential to comprehend how moisture, drying temperature, and extraction technique interact. This chapter tries to clarify these interactions in order to offer helpful information to researchers, food scientists, and business experts who are considering using polyphenols as allnatural substances to improve lipid quality.
