## 3 Extraction of Vital Products
### Bioactive Compounds
The total phenolic content (TPC) enhanced with a change in the extraction temperature from 20 to 70 \({}^{\circ}\)C, and the yield at 70 \({}^{\circ}\)C was measured to be two times higher than that obtained at 20 \({}^{\circ}\)C via conventional extraction. As phenolics present in whole grains are known for their antioxidant properties, the total antioxidant capacity (TAC) of the extract was evaluated. Five phenolic acids (gallic acid, caffe acid, proto- catechuic acid, p-cumaric acid, ferulic acid) were identified via HPLC-DAD in oat bran [16]. Moreover, the extraction of anthocyanins and phenolics from Blueberry (_Vaccinium ashei_) wine pomace has shown superior efficiency compared to conventional solvent extraction (CSE). The TA (total anthocyanin) and TP (total phenolic) yield were 2.5 and 3.2-folds higher than CSE and considering the extraction time, CSE took 35 min to yield 5.08 mg/g of TP, while UAE took only 30 min to yield 16.41 mg/g (Table 1) [17]. Pomegranate and orange peel are a rich source of polyphenols, which could be effectively extracted via UAE. [PERSON] et al. [18] successfully extracted phenolic compounds (punicalagin and hydroxybenzoic acids) from pomeranate peel (Malas variety) via a pulsed ultrasound-assisted technique. Better efficiency in the extraction of phenolics was achieved under an ultrasonic intensity of 105 W/cm\({}^{2}\) and by following a duty cycle of 50% for a short time (10 min). UAE under pulse mode delivered an extraction yield of 41.6% within just 10 min, as compared to 45.4% via continuous sonication within 30 min. Considering the extraction of polyphenols from orange (_Citrus sinensis L._) peel, [PERSON] et al. [19] effectively extracted flavanone glycosides via UAE, which are known for their antioxidant properties. Similarly, UAE has proved to be better than conventional maceration method for the extraction of phenolic compounds from mandarin (_Citrus reticulata Blanco cv. [PERSON]_) peel, with 1.77 times higher yield than maceration [20]. UAE has been effectively implemented during the extraction of polyphenols (anthocyanins, phenolic compounds) from mulberry (_Morus nigra_) pulp. Anthocyanins, such as cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, cyanidin-3-O-(6\"-malonyl-glucoside) and cyanidin-3-O-(6\"-dioxalyl-glucoside) were detected via UHPLC-MS analysis. Extraction temperature and solvent composition (methanol: water) were identified as vital factors influencing the yield of anthocyanins (48 \({}^{\circ}\)C and 76% methanol) and total phenolic compounds (64 \({}^{\circ}\)C and 61% methanol) from mulberry pulp [21]. [PERSON] et al. [22] implemented NPC for the extraction of seciosolariciresinol diglucoside (SDG) from flaxseed. NPC achieved a higher extraction yield of SDG as compared to conventional methods, and the yield, as well as purity of the extract was comparable to UAE. NPC based method has been employed for the extraction of flavonoids biochanin A and genistein, from _Dalbergia odorifera_ leaves, which possessed an excellent antioxidant activity. Under optimum conditions, an extraction yield of 1.583 and 0.933 mg/g DW was obtained for biochanin A and genistein respectively (Table 2) [23]. Pigeon pea [_Cajanus cajan (L.) Millsp._] is one of the most examined food legumes, because of its antioxidant, anti-inflammatory, antispasmodic and antimicrobial activities. Cajaninstilbene acid (CSA) and pinostrobin were extracted from pigeon pea leaves, and under optimized conditions, the yield via NPC method was comparable to UAE [24]. [PERSON] et al. [25] investigated the extraction of genistein and genistin from pigeon pea roots while obtaining a maximum yield of 0.418 and 0.398 mg/g respectively under optimized conditions. Table 2 listed the vital products extracted by HC and NPC based methods. Polysaccharides (PS) represent a vital category of bioactive compounds as they exhibit numerous medicinal properties and can be extracted from food to fungi. Polysaccharides have shown to exhibit antitumor, anticancer, anti-hepatitis B, and antioxidant activities.