Citrus aurantium

Participants were matched for age, body mass, and FFM and randomly assigned to ingest in a double-blind manner either: (1) a flavored dextrose placebo (PLA); (2) a PWS containing beta-alanine (3 g), creatine nitrate as a salt (2 g), arginine alpha-ketoglutarate (2 g), N-Acetyl-L-Tyrosine (300 mg), caffeine (284 mg), Mucuna pruiriens extract standardized for 15% L-Dopa (15 mg), Vitamin C as Ascorbic Acid (500 mg), niacin (60 mg), folate as folic acid (50 mg), and 70 mg of Vitamin B12 as Methylcobalamin (Cellucor C4 Pre-Workout, Nutrabolt, Bryan, TX); or, 3.) the PWS with Citrus aurantium (PWS + S) extract standardized for 30% synephrine (20 mg) (Nutratech Inc., Caldwell, NJ). Supplements were independently packaged by a third party into coded single foil packets for double-blind administration following Good Manufacturing Practices and certified to contain the aforementioned ingredients by VMI Nutrition (Salt Lake City, UT). All supplements had similar color and powdered texture. Participants were instructed to ingest one foil packet per day approximately 15–30 min prior to exercise on training days and in the morning with breakfast on non-training days. Supplement compliance was verified by weekly compliance verification and collecting and counting empty packets.

The present study was approved by the Research Ethics Committee of the University of Aegean, Greece (no. 13, 18 February 2022). All participants provided written informed consent in accordance with the Declaration of Helsinki [37 (link)]. Any information that might reveal the identity of the study participants was omitted, and the participants were number coded.
The study was conducted from March to December 2022. Participants were recruited randomly by the research team via social media and online announcements at the Agricultural University of Athens and the University of Aegean, Lemnos, Island, Greece. All participants were randomly selected, and no further educational/informative leaflets were given about the fortified dairy products.
Two organoleptic evaluations were performed as presented in Figure 1. The first organoleptic study was performed in Athens, Greece (Agricultural University of Athens) with a total number of 22 participants being women (n = 19) and men (n = 3) and the second organoleptic study was implemented in Lemnos Island, Greece (University of Aegean) with a total number of 25 participants, women (n = 18) and men (n = 7). In both studies, unlabeled non-colored disposable plastic containers with 20 g of fortified dairy product were provided to the participants. The studies were conducted in a room with 20–22 °C temperature and 50–65% humidity. Enhanced dairy products were provided to each of the participants, and they did not have any information on which type of fortified product they were censoring. Furthermore, a questionnaire was administered to each participant to evaluate the appearance, taste, flavor, and smell of the product on a scale from ‘1 = I do not like it’ to ‘5 = I highly like it’. Between each sample, the participants were instructed to drink water to clean their mouth.
During the first organoleptic study, the participants tested and evaluated 4 different yogurt samples and 3 vegan yogurt samples. In more detail, plain yogurt without the addition of any extract, yogurt with St. John’s Wort extract, yogurt with dittany extract, yogurt with pennyroyal, and yogurt with lemon balm extract were provided to each participant. After finishing the evaluation of the above samples, participants then tested and evaluated the vegan yogurt samples: a control without any extract added, a vegan yogurt with spearmint, and a vegan yogurt with lavender. The samples were provided in different orders for each participant.
During the second organoleptic study, the participants tested 4 kefir samples and 4 cream cheese samples. Specifically, a control kefir with no added extract, kefir with bitter orange peel extract, kefir with both bitter orange peel and lemon peel extracts, and kefir with bitter orange peel and rosehip seed extracts were evaluated. After finishing with the evaluation of the above samples, participants proceeded with the evaluation of cream cheese samples: plain cream cheese with no added extract, cream cheese with mountain tea extract, cream cheese with St. John’s Wort extract, and cream cheese with both mountain tea and St. John’s wort extracts. The samples were provided in different orders for each participant.

Plant byproduct and herb samples were collected from Lemnos Island, North Aegean, Greece, between June and October 2021. The samples consisted of bitter byproducts from orange (Citrus aurantium) peel (n = 5), lemon (Citrus limon) peel (n = 5), rosehip (Rosa canina) seed (n = 5), as well as mountain tea (Sideritis spp.) (n = 10), St. John’s wort (Hypericum perforatum) (n = 10), dittany (Origanum dictamnus) (n = 5), pennyroyal (Mentha pulegium L.) (n = 10), lemon balm (Melissa oficinallis) (n = 5), spearmint (Mentha spicata L.) (n = 10), and lavender (Lavandula angustifolia) (n = 5). At least 5 samples were used from each food product and pooled together. All samples were dried in a drying heating oven (Binder GmbH, Tuttlingen, Germany) at 60 °C for 12 h and kept in sealed bags until extract preparation.
Extracts were prepared by adding in a flask 2 g of each herb or 10 g of each plant byproduct to 100 mL of dH₂O. Each flask was then placed in an Elmasonic P 70 H ultrasound water bath (Elma-Hans Schmidbauer GmbH & Co., Singen, Germany) at 70 °C and 80 Hz for 60 min. Filtration of the extracts was performed by filter paper.