## 4 Health Benefits and Composition of Kiwi By-Products  
Kiwi and its products are included among the healthy fruits highly demanded by consumers, due to their nutritional value and proposed health benefits. Nevertheless, the processing of such products contribute significantly to the increased amount of by-products available, which further advances the related environmental issues and waste management costs of such agri-food bio-waste. On the other hand, it seems that a considerable amount of highly valuable kiwi nutrients and bioactives remain in its by-products after processing. Thus, the recovery and valorization of such valuable bioactive compounds from kiwi  
\begin{table}
\begin{tabular}{c c c} \hline
**Proximate (g/100 g)** & **Nutritional Value** & **Reference** \\ \hline Water & 81.07–83.49 & [32] \\ Energy (kcal/KJ) & 61/255 & [32] \\ Total Fat & 0.5–0.52 & [32] \\ Sugar & 8.99–9 & [32] \\ Fiber & 3 & [32] \\ Total carbohydrate & 14.66–14.7 (15) & [32] \\ Total protein & 1.1–1.14 & [32] \\
**Nutrients (g/100 g)** & & \\ Vitamin C & 92.7 & [32] \\ Vitamin E & 1.46 & [32] \\ Folate & 25 & [32] \\
**Pigments (ug/100 g)** & & \\ Beta-carotene & 52, 170 & [29;32] \\ Lutein & 122, 160 & [29;32] \\ Violaxanthin & nd, 110 & [29;32] \\
9’-cis neoxanthin & nd, 120 & [29;32] \\ Total carotenoids & nd, 590 & [29;32] \\ Chlorophyll a & nd, 550 & [29;32] \\ Chlorophyll b & nd, 440 & [29;32] \\ Total chlorophylls & nd, 990 & [29;32] \\
**Minerals (mg/100 g)** & & \\ Calcium & 34 & [30;32] \\ Iron & 0.31 & [30;32] \\ Magnesium & 17 & [30;32] \\ Phosphorus & 34 & [30;32] \\ Potassium & 312 & [30;32] \\ Sodium & 3 & [30;32] \\ Zinc & 0.14 & [30;32] \\ Copper & 013 & [30;32] \\ Manganese & 0.098 & [30;32] \\ Selenium & 0.2 & [30;32] \\
**Phenolics** & **Juice = mg/L** & \\  & **Whole fruit = mg/100 g** & \\  & 180–220 mg/100 g, & \\  & 96 mg/100 g, & \\ Total phenolics & 700 mg/L for (fujec) and 78–103 & [27;33;34] \\  & mg/g (fresh weight) & \\ Protocatechic acid & 0.24 (mg/L), 2634.27 (mg/kg) & [27;35] \\ Catechin & nd, 411.24 (mg/kg) & [27;35] \\ Chlorogenic acid & 0.71(mg/L), 243.10 (mg/kg) & [27;35] \\ Caffe acid & 0.09 (mg/L), 8.14 (mg/kg) & [27;35] \\ Epicatechin & 2.62 (mg/L), nd & [27;35] \\ P-coumaric & 0.06 (mg/L), nd & [27;35] \\ Quercetin 3-rutinoside & 0.41 (mg/L) & [27] \\ Quercetin 3-glucose & 0.20 (mg/L) & [27] \\ Kaempfer1 3-rutinoside & 0.20 (mg/L) & [27] \\ Quercetin 3-rhamnoside & 0.45 (mg/L) & [27] \\ Kaempfer1 3-rhamnoside & 0.05 (mg/L) & [27] \\ \hline \end{tabular}
\end{table}
Table 2: Characteristic nutritional content and composition of dietary bioactives in kiwi.  
by-products, via several applications, is of paramount importance for the sustainable development of this fruit, in the context of the design of a circular economy. Promising kiwi by-products, that are not considered edible and are not used for juice production, and which are now considered more as sustainable natural resources rather than bio-waste, are the set of different peels, the residual pulp/pomace, the seeds, and the leaves of the kiwi, which represent up to 30% of total kiwi fruit production. These by-products constitute substantial sources of the nutritionally important bioactive compounds found in kiwi, mainly phenolics, vitamins, and pigments, which are retained in such by-products, as shown in Figure 4[34; 36; 37].