*Eat Tasty and Healthy: Role of Polyphenols in Functional Foods DOI: http://dx.doi.org/10.5772/intechopen.96577*


**Table 2.**

*Effect of fortification with PC in sensory properties of functional foods.*

#### *Eat Tasty and Healthy: Role of Polyphenols in Functional Foods DOI: http://dx.doi.org/10.5772/intechopen.96577*

flavor notes and color. These authors studied the stability of PC during the baking process. Within the PC, the most stable ones were as follows: γ-resorcylic acid (loss of 11%) < gallic acid (loss of 18%) < tyrosol (loss of 21%) < catechin (loss of 31%) < isovanilic acid. Moreover, procyanidins B1 and B2, which were identified in the pomace were not retained after the baking process. At the end, there was an almost tenfold increase in bioactive compounds in the biscuits enriched with 30% of pomace, from 0.11 mg.g−1 (control) to 1.07 mg.g−1.

The stability of PC at the end of the baking process was also assessed upon supplementation of biscuits and bread with green tea extracts to increase the antioxidant ability of the final product [126]. While it was found ca. 30 and 21% of retention of epicatechin gallate and epigallocatechin gallate, respectively, for biscuits supplemented with 300 mg green tea extract per 100 g flour [127], the retention in freshly baked bread were ca. 83 and 91%, respectively [105]. At the end, it was determined that one piece of bread (53 g) containing 150 mg of GTE/100 g of flour will provide 28 mg of tea catechins, which is ∼35% of those infused from one green tea bag (2 g). However, none of these studies inferred about the sensory profile of these food products.

Ross and colleagues studied the consumer acceptance of grape-seed (GS) flour-containing food products, namely pancakes and noodles [128]. The GS flour was obtained from winemaking by-products from different grapes (Merlot and Cabernet Sauvignon). Despite the PC content of the GS flour was not characterized, this organic material is well-known to have a high content in procyanidins. It was observed that the supplementation with GS flour led to a decrease on consumer acceptability of pancakes and noodles, especially for taste (bitterness), mouthfeel (astringency) and texture. This is not surprising since astringency and bitterness are the two main descriptors of procyanidins.

Coffee sylverskin, a byproduct of coffee industry highly rich in PC, has been also evaluated to supplement baking products such as cookies [129] or cakes [117]. The supplementation with this byproduct had improved the functional quality of cookies by increasing their PC contents, antioxidant capacities and *in vitro* bioaccessibilities. However, all supplementation concentrations had lowered the consumers' flavor-taste scores and overall acceptability, which was attributed to the bitter taste of this food matrix.

The use of apple pomace has functional ingredient has been recently reviewed [130] and has been applied with success in several bakery products, namely bread, scones, cakes, and muffins. The addition of 5% of the apple pomace was found to not significantly impact the sensory properties of cookies [131].

### *5.2.2 Addition of PC to coffee*

GS pomace (derived from Chardonnay winemaking), was evaluated to be used as a functional ingredient in brewed coffee [132]. This GS pomace could be added at 6.25% replacement without significantly affecting the overall consumer acceptance of coffee compared to the control (0%). These authors chose the GS pomace from a white grape variety because it has lower levels of tannins and no anthocyanins compared to red varieties, and so it can be expected a lower contribution to bitterness and astringency. In fact, not only astringency and bitterness did not increase upon replacement as it was observed their significant reduction for all replacement percentages in comparison to the control coffee. Although the authors do not discuss this result, one hypothesis is that the white grape varieties are also well-known for a higher content in sugar. Mouthf eel and texture, pancakes made with Cabernet Sauvignon (25% replacement) showed the lowest acceptance, significantly different from 30% replacement with a higher acceptance. This result suggested that the

impact of GSF concentration was more apparent for in-mouth attributes mouthf eel and texture, pancakes made with Cabernet Sauvignon (25% replacement) showed the lowest acceptance, significantly different from 30% replacement with a higher acceptance. This result suggested that the impact of GSF concentration was more apparent for in-mouth attributes.

#### *5.2.3 Addition of PC to pasta*

Gaita and colleagues supplemented pasta with grape pomace [133]. These authors quantified the PC in control pasta and in the fortified one and showed an effective enhancement of PC levels. These increases were dependent on the pomace grape variety, but in general were effective for gallic, caffeic, ferulic and coumaric acids, rutin, and resveratrol. Moreover, the pasta samples with addition of pomace to a level of 3 and 6% showed improved sensory characteristics versus the control sample while the kneading and dough processing operations have not been affected.

#### *5.2.4 Addition of PC to dairy products*

Grape pomace of Chardonnay, Moscato and Pinot noir varieties has been used to supplement yogurt [116]. A total of nine PC were characterized in fortified yogurt depending on the origin of the grape pomace: phenolic acids (gallic acid, protocatechuic acid and vanillic acid); flavan-3-ols (procyanidin B1, catechin and epicatechin) and flavonols (rutin and quercetin). For most of these PC, they were stable at least for 21 days. Independently of the origin of grape pomace, all enriched yogurts add a lower liking score, especially regarding the organoleptic properties (flavor and taste). The Moscato yogurt was less accepted, with a very low mean liking score, particularly for taste and flavor. In contrast, Chardonnay was the sample with the highest mean scores for appearance, flavor and overall liking. Several informal attributes were reported by tasters such as "not enough sweet," with "unpleasant flavors", "not homogeneous" and "grainy/sandy." However, no correlation was found with the quantified PC.

Komes and colleagues used plant extracts (lemon balm, mint, lavender, rosemary and sage) for the development of functional and nutritively valuable goat's milkbased beverages [121]. The concentration of bioactive PC (rosmarinic acid, hydroxycinnamic acid derivatives and luteolin derivatives) were significantly increased in goat's milk in dependence of the added plant extract. While the extracts alone were found to be bitter and astringent, when added to the milk, some of the final beverages had acceptable levels of these two taste properties. However, the beverage enriched with lavender extract was characterized by the highest intensity of bitterness and astringency and thus consequently low overall acceptability. On the other hand, the beverage with mint extract was one of the preferred ones. Interestingly, this beverage was the one with the highest concentration of total PC, total flavonoids and antioxidant ability while was one of the less bitter and astringent beverages. This suggests that the profile of the PC present (not the concentration) should be the key to the perceived taste properties. At the end, apart from the accomplished bioactive enrichment and stability, the new functional beverages exhibited significantly enhanced sensorial properties when compared to plain goat's milk, with the highest overall satisfactoriness determined for samples fortified with mint and rosemary extracts.

#### *5.2.5 Addition of PC to meat products*

Tomato and derived-processed products generates considerable amount of by-products in the form of pomace, peel and seeds. They are rich sources of dietary

#### *Eat Tasty and Healthy: Role of Polyphenols in Functional Foods DOI: http://dx.doi.org/10.5772/intechopen.96577*

fiber and bioactive compounds. In addition to carotenes, tomato by-products are rich in vitamins as well as PC, namely phenolic acids and flavonoids. Due to their color properties, these by-products have major applications in meat and meatderived food products, as reviewed recently [134]. The higher antioxidant activity observed for tomato waste (composed by skin and seeds) has been related with the fact that this product had the highest phenolic and flavonoid amounts, in particular rutin, quercitrin and naringenin may be more efficient as antioxidant than carotenoids with respect to preventing lipid oxidation in pressurized chicken meat. Different researches have observed some general trends in the application of tomato by-products, namely improved nutritional quality, reduced lipid oxidation and increased stability during the shelf-life period of meat products, while maintaining or increasing sensory properties and general satisfactoriness.

Green tea extracts have been also used in meat products (e.g. raw beef and chicken patties). In raw beef and chicken patties, the tea catechins treatment resulted in no significant differences in the sensory flavor, taste, and tenderness [135]. Moreover, even only a marinade with green tea instead of enrichment of meat was found to reduce the formation of heterocyclic aromatic amines while bitterness and astringency perception was neglectable [136].

At the end, surprisingly, the sensory profile reported for green tea extractsupplemented meat products (turkey burgers [126], raw beef and chicken patties [135], pan-fried beef [136] as well as other food products (biscuits, cake [137]) is usually equal or superior to the control conditions (usually containing synthetic antioxidants). Since green tea extract is well-known for its bitter and astringent taste properties this could be probably due to interactions with the food matrix compounds, as discussed ahead.

## **5.3 Interactions of phenolic compounds with food macronutrients**

In the human diet, PC are generally consumed in foods along with macronutrients (e.g. proteins, lipids and carbohydrates). The effect of interactions between PC and food constituents is a very important topic since they can have several implications on their sensory properties and lastly on their biological effects.
