Fortification of yogurt with fruits of Hottentot-fig (Carpobrotus edulis L.)

Bratkič, Kim (author), Čanžek Majhenič, Andreja (mentor), Custodio, Luisa Margarida (co-mentor)

Food additives are crucial in the food industry to ensure a longer shelf-life of food products, enable its mass production, widespread distribution, and expansion to new markets. But the intake of synthetic food additives is linked with a higher incidence of several health problems, including allergies and cancer. Additionally, consumers are determined in pursuing healthier habits by the use of foods promoting positive effects on health in addition to their basic nutritional purposes, i.e., functional foods. Salt-tolerant plants, i.e., halophytes, such as Carpobrotus edulis have evolved several adaptations in response to different stresses, such as high salinity levels, including the synthesis of highly bioactive compounds, such as phenolics. This is the first study done on the addition Hottentot-fig extract as an additive into yogurts, and it shows promising results. The incorporation of Hottentot-fig extract into dairy matrix showed a significantly higher antioxidant activity than the control sample at all storage times and can be considered as a source of phenolics. Moreover, the extracts showed to be nontoxic. Overall, the addition of extracts also did not negatively affect quality parameters such as syneresis and water holding capacity and possibly even improve the quality of yogurt, with phenolics interacting with yogurt proteins and stabilizing the gel matrix. In terms of physiochemical properties (pH and color) were not affected by the addition of the Hottentot-fig extracts. While the addition of the Hottentot-fig extracts caused a slight change in nutritional properties, such as increased ash content.

• Language: English
• Keywords: Carpobrotus edulis, bioactivity, halophyte plants, phenolics, yogurt, functional foods, physicochemical properties, nutritional properties
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [K. Bratkič]
• Year: 2022
• PID: 20.500.12556/RUL-136794
• UDC: 637.146.34:664.022.3:641.1
• COBISS.SI-ID: 108795907
• Publication date in RUL: 21.05.2022

Secondary language

• Language: Slovenian
• Title: Obogatitev jogurta s plodovi rastline Hottentot-fig (Carpobrotus edulis L.)

Abstract

Aditivi za živila so v živilski industriji ključnega pomena za zagotavljanje daljšega roka trajanja živil, s čimer omogočajo njihovo masovno proizvodnje ter širjenje na nove trge. Toda vnos sintetičnih aditivov v živila je povezan z večjo pojavnostjo zdravstvenih težav, vključno s pojavom alergij in rakavih obolenj. Potrošniki postajajo dandanes vse bolj ozaveščeni o zdravih prehranskih navadah. To se kaže v povečani uporabi t. i. funkcionalnih živil, ki poleg svojih osnovnih prehranskih funkcij izkazujejo dodatne, zdravju pozitivne učinke. Eno takih, potencialno funkcionalnih živil, smo raziskovali v naši nalogi, kjer smo kot osnovno živilo uporabili jogurt in ga obogatili z izvlečki rastline Carpobrotus edulis. Slednja je slanuša ali halofit, ki je razvila različne prilagoditve na okoljske obremenitve, kot so visoke ravni slanosti. To je prva študija o dodatku izvlečka olupkov Hottentot-fig v jogurte in kaže obetavne rezultate. V času shranjevanja so jogurti z dodatkom izvlečka izkazovali znatno večjo antioksidativno aktivnost kot kontrolni vzorci brez izvlečkov. Dodatek izvlečkov Hottentot-fig v jogurte bi tako lahko predstavljal prehranski vir bioaktivnih fenolnih spojin. Izkazalo se je tudi, da so izvlečki nestrupeni in niso negativno vplivali na kakovostne parametre, kot sta sinereza in sposobnost zadrževanja vode, temveč so jih morda celo izboljšali. Interakcije polifenolov z beljakovinami jogurta bi namreč lahko stabilizirale matriks jogurta. Dodatek izvlečkov ni vplival na fizikalno-kemijske lastnosti (pH in barvo) jogurtov, povzročil pa je rahlo spremembo hranilne sestave, med drugim povečanje vsebnosti pepela v obogatenih jogurtih.

• Keywords: Carpobrotus edulis, bioaktivnost, halofilne rastline, fenolne spojine, jogurt, funkcionalna živila, fizikalno-kemijske lastnosti, hranilna sestava