## 4 Health Benefits and Composition of Kiwi By-Products
### Kiwi Pomace  
The pomace of kiwi fruit, like any fruit, essentially consists of a set of by-products, i.e., the skin, leaves, and seeds condensed into a form of residue pulp. Pomace is enriched with a series of bioactives derived from its components and can be an important source of nutrients. The main starting point for the production of pomace is the kiwi fruit industries that discard a high amount of the abovementioned by-products, during the processing of the fruit. However, as a naturally produced form of bio-waste, it is a shame that it is not exploited, as it can be used for the creation of new functional products in the fields of cosmetics, food products, and pharmaceuticals. A wide range of phenolics are hidden in pomace and are mainly compounds, such as chlorogenic acid, p-coumaric acid, catechin, protocatechuic acid, and derivatives of caffeic acid (Table 3). These types of bio-waste are also characterized by a high water and sugar content. In research carried out on extracts of kiwi pomace and pears, a composition of 12.8% polysaccharides was found in kiwi pomace, while dietary fiber did not fail to make an appearance, with a value of 25.8% on a dry weight basis. Here, the primary exponent of soluble fiber is pectin, in the form of oligosaccharides, and with a total percentage of 7% DW, which, if reached through an enzymatic breakdown process, might aid antiaging, cause a reduction in arteriosclerosis, and cause the prevention of diabetes via its prebiotic effects. Insoluble fibers, on the other hand, are represented by protopectin, in the order of 18.7%. Specialized food items tailored for individuals dealing with diabetes, heart issues, and obesity can be enhanced with both soluble and insoluble dietary fiber sourced from the often overlooked kiwi fruit. Another research paper suggested that by employing acid, alkaline, and enzymatic extraction methods, it is possible to obtain 33 g/100 g of soluble and 72 g/100 g on a dry weight basis of insoluble dietary fiber. In this scenario, an ultrafine powder derived from insoluble dietary fiber found in a by-product kiwi fruit beverage was incorporated as a replacement in low-fat meat, which led to an improvement in its physicochemical quality and textural traits [34; 37; 42; 43]. Hence, the beneficial properties offered by a simple extract of one of the bio-products of this small fruit are apparent.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Composition** & **Amount** & **By-Product** \\ \hline Total phenolics & 329 mg/g & Seeds [38] \\ Total proteins & 12.62\% & Peels [34] \\  & 12.72–14.94\% & Seeds [38] \\ Total lipids & 3.7\% & Peels [34] \\  & 28.3–35\% & Seeds [11] \\ Total carotenoids & 5.70 \(\pm\) 0.033 mg/g DW & Peels [34] \\  & 1.55 \(\pm\) 0.093 & Pomace [34] \\
**Phenolic profile** & 14.3–24.6 (GAE) & Peels [34; 35] \\  & 9.71 \(\pm\) 0.28 mg GAE/g DW & \\  & 3.79 \(\pm\) 0.15 mg GAE/g DW & Pomace [34] \\  & 200 mg/g & Leaf [11] \\ \hline \hline \end{tabular}
\end{table}
Table 3: The composition of bioactives in Kiwi by-products.  
Valorization of Bioactive Compounds from Kiwi By-Products in the Application of Health-Promoting Functional Foods, Supplements, and Nutraceuticalials