Upgrading the physiochemical and sensory quality of yogurt by incorporating polyphenol-enriched citrus pomaces with antioxidant, antimicrobial, and antitumor activities

Abstract

Industrial pomaces are cheap sources of phenolic compounds and fibers but dumping them in landfills has negative environmental and health consequences. Therefore, valorizing these wastes in the food industry as additives significantly enhances the final product. In this study, the citrus pomaces, orange pomace (OP), mandarin pomace (MP), and lemon pomace (LP) were collected by a juice company and subjected to producing polyphenols and fiber-enriched fractions, which are included in functional yogurt; the pomace powder with different levels (1, 3, and 5%) was homogenized in cooled pasteurized milk with other ingredients (sugar and starter) before processing the yogurt fermentation. The HPLC phenolic profile showed higher phenolic content in OP extract, i.e., gallic acid (1,702.65), chlorogenic acid (1,256.22), naringenin (6,450.57), catechin (1,680.65), and propyl gallate (1,120.37) ppm with massive increases over MP (1.34–37 times) and LP (1.49–5 times). The OP extract successfully scavenged 87% of DPPH with a relative increase of about 16 and 32% over LP and MP, respectively. Additionally, it inhibits 77–90% of microbial growth at 5–8 μg/mL while killing them in the 9–14 μg/mL range. Furthermore, OP extract successfully reduced 77% of human breast carcinoma. Each of pomace powder sample (OP, MP, LP) was added to yogurt at three levels; 1, 3, and 5%, while the physiochemical, sensorial, and microbial changes were monitored during 21 days of cold storage. OP yogurt had the highest pH and lowest acidity, while LP yogurt recorded the reverse. High fat and total soluble solids (TSS) content are observed in OP yogurt because of the high fiber content in OP. The pH values of all yogurt samples decreased, while acidity, fat, and TSS increased at the end of the storage period. The OP yogurts 1 and 3% scored higher in color, flavor, and structure than other samples. By measuring the microbial load of yogurt samples, the OP (1 and 3%) contributes to the growth of probiotics (Lactobacillus spp) in yogurt samples and reduces harmful microbes. Using citrus pomace as a source of polyphenols and fiber in functional foods is recommended to enhance their physiochemical and sensory quality.

Potential Antitumor Effect of Functional Yogurts Formulated with Prebiotics from Cereals and a Consortium of Probiotic Bacteria

“…The level of polyphenolic compounds found in products with or without cereals is similar to the results obtained by Arafoui et al [ 53 ] which reported a level of 8.5 mg GAE/100 g product in the yogurt formulated as a control. Other authors formulated yogurts with a high content of polyphenolic compounds by adding some subproducts which resulted after squeezing citrus fruits, strawberries, mulberry, dragon fruit, or passiflora [ 54 , 55 , 56 , 57 , 58 , 59 ]. In this case, the concentration of polyphenolic compounds ranged between 0.56 mgGAE/g and 1.28 mgGAE/g for yogurts with citrus [ 54 ] and between 20 mgGAE/mL and 64.43 mgGAE/mL for yogurt formulated with dragon fruit [ 55 ].…”

“…Other authors formulated yogurts with a high content of polyphenolic compounds by adding some subproducts which resulted after squeezing citrus fruits, strawberries, mulberry, dragon fruit, or passiflora [ 54 , 55 , 56 , 57 , 58 , 59 ]. In this case, the concentration of polyphenolic compounds ranged between 0.56 mgGAE/g and 1.28 mgGAE/g for yogurts with citrus [ 54 ] and between 20 mgGAE/mL and 64.43 mgGAE/mL for yogurt formulated with dragon fruit [ 55 ]. In this last case, it is important to mention that the yogurt formulated with dragon fruit used probiotic bacteria supplied by Cristian Hansen [ 59 ].…”

Exploring Phenolic Compounds in Crop By-Products for Cosmetic Efficacy

“…Accordingly, the peels of citrus fruits, particularly oranges, have higher phenolic content compared to the edible portions, containing compounds like hesperidin. The water extracts of citrus pomace also have significant phenolic and flavonoid content [ 21 ], with high contents of hesperetin-7- O -rutinoside, quercetin, peonidin, and apigenin [ 20 , 21 , 22 , 23 ].…”

“… Species Phenolic Compounds Concentration (mg g −1 DW) References Artichoke Apigenin, Caffeic acid , Caffeoylquinic acid, Chlorogenic acid, Coumaric acid, Cynarin, Ferulic acid , Luteolin, Naringenin, Narirutin, Quinic acid 1.99–27.21 [ 8 , 10 , 11 , 12 ] Broccoli Caffeic acid , Chlorogenic acid, Coumaroylquinic acid, Ferulic acid , Kaempferol, Quercetin , Sinapic acid 6.70–163.18 [ 14 , 16 , 18 , 19 ] Cauliflower Caffeic acid , Coumaric acid, Ferulic acid , Kaempferol, Lutein, Quercetin , Sinapic acid 3.45–10.70 [ 17 , 40 , 41 ] Citrus sp. Apigenin, Benzoic acid, Caffeic acid, Caffeine, Caffeoylquinic acid, Caffeoyltartaric acid, Catechol, Catechin , Chlorogenic acid, Cinnamic acid, Cyanidin, Delphinidin, Dihydroxyflavone, Diosmin, Ellagic acid, Eriocitrin, Eriodictyol, Ferulic acid, Gallic acid , Gentisic acid, Hesperetin, Isorhamnetin, Isosakuranetin, Kaempferol, Luteolin, Malvidin, Myricetin, Naringenin, Naringin, Narirutin, Neoeriocitrin, Neohesperidin, 4-hydroxybenzoic acid, Pelargonidin, Peonidin, Phloretin, Propylgallate, Quercetin , Resveratrol , Rosmarinic acid , Rutin, Scopoletin, Sinapic acid, Sinensetin, Syringic acid, Vanillin, Vanillic acid, Vitexin 3.00–196.20 [ 20 , 21 , 22 , 23 , …”

Extraction, characterization of polyphenols from certain medicinal plants and evaluation of their antioxidant, antitumor, antidiabetic, antimicrobial properties, and potential use in human nutrition

“…Ten grams from each medicinal plant's powder was extracted with 200 mL of 80% methanol for 1 h in an ultrasonic bath (Transsonic-700, 37 kHz, Germany) at 50 • C. The MPPE was centrifuged at 3,000 rpm for 10 min; the supernatant was obtained, and the residues were discarded. The solvent in the supernatant was evaporated using an R-200-Buchi-rotary evaporator (Switzerland), and the concentrated MPPE was obtained; The yield percentage of MPPE was evaluated using the following equation, the methanol-free extract was lyophilized and retained in water when the use (39).…”