Development of a Coffee Pulp Infusion as a Strategy for Recovery After Moderate Physical Exercise in a Healthy Population.

Background and Rationale:

Physical exercise induces transient physiological oxidative stress, acute inflammation, and microscopic skeletal muscle damage, which are often characterized by an increase in circulating biomarkers such as C-reactive protein (CRP), creatine kinase (CK), and lactate dehydrogenase (LDH). While these processes trigger long-term muscular adaptations in professional athletes, in the amateur and recreational sports population, they can cause prolonged muscle soreness and fatigue, limiting well-being and exercise adherence.

Coffee pulp (CP) or "cascara" is the main by-product of wet coffee processing and has been traditionally discarded as agricultural waste. However, it is an abundant source of valuable bioactive compounds, notably phenolic acids (chlorogenic, protocatechuic, and gallic acids), flavonoids, and methylxanthines like caffeine. Recently, under Regulation (EU) 2015/2283, the European Union authorized dried coffee cherry pulp and its infusion as a traditional novel food, establishing its safety baseline for human consumption. Leveraging its prominent in vitro and cellular antioxidant and anti-inflammatory properties, this study evaluates an optimized, sustainable beverage formulation designed specifically to facilitate and enhance physiological recovery after moderate physical activity.

Furthermore, clinical sports nutrition literature frequently exhibits a severe gender bias, as most supplementation trials are conducted strictly on well-trained male cohorts. The COPULP-REC trial addresses this scientific gap by systematically incorporating the sex and gender dimension, exploring distinct baseline profiles and post-intervention recovery responses between men and women.

Study Design and Formulation Protocol:

This is a randomized, double-blind, placebo-controlled, parallel-group, longitudinal nutritional intervention trial. The investigation is divided into two operational phases:

1. Infusion Optimization and Placebo Formulation: The mass transfer rate of bioactive compounds from the coffee pulp matrix to water is optimized using response surface methodology (RSM) via a Full Factorial experimental design. Parameters analyzed include extraction time, coffee pulp-to-water ratio, and grain particle size. The Selected optimized formulation contains stable, standardized amounts of total polyphenols and caffeine. A sensory-matched placebo infusion is developed using wheat bran, which exhibits negligible bioactive potential. To preserve the double-blind design, the placebo is structurally matched in appearance, color, and flavor using food-grade additives, validated through discriminatory triangle testing panel reviews.
2. Clinical Trial Intervention: Enrolled participants are randomly assigned to either the experimental group (optimized coffee pulp infusion) or the control group (sensory-matched wheat bran placebo) in a 1:1 allocation ratio. Randomization keys are held by an unblinded data coordinator not involved in direct participant assessment.

Experimental Procedures and Sample Collection Timeline:

The longitudinal intervention spans 45 consecutive days, during which participants consume exactly two infusions per day (one in the morning and one at night). The clinical flow consists of 6 sequential appointments:

• Appointment 1: Participant screening, signed informed consent, baseline medical history, and anthropometric profiling.
• Appointment 2: Dietary habit index baseline mapping, minor cardiovascular familiarization, and individual repetition maximum (1RM) physical calculations.
• Appointment 3 (Basal Exercise Challenge): Participants undergo a standardized acute physical exercise challenge consisting of a lower-body leg extension routine (5 sets at 85% of their predetermined 1RM). Cardiorespiratory monitoring is tracked immediately pre- and post-exercise.
• Appointment 4 (24h Post-Exercise Basal): Occurring at the physiological peak of muscle damage. Morning spot urine and capillary blood drops are collected. Participants receive their 45-day coded allotment box of infusions and standardized preparation equipment (mugs and sand timers).
• Appointment 5 (Post-Intervention Exercise Challenge): Completed after 45 days of compliance. The standardized heavy-load leg extension protocol (5 sets at 85% 1RM) is repeated under identical conditions.
• Appointment 6 (24h Post-Exercise Intervention): Final biological samples (urine and capillary blood) are processed to capture the post-supplementation recovery response.

Laboratory and Analytical Methodologies:

• Hemodynamic Tracking: Systolic blood pressure, diastolic blood pressure, heart rate, and capillary oxygen saturation are monitored via automated oscillometric and finger oximetry protocols.
• Body Composition Analysis: Segmental bioelectrical impedance is utilized to longitudinally map weight, fat mass percentage, muscle mass percentage, total body water, and visceral fat shifts.
• Biochemical Plasma and Urine Profiling: Capillary blood extraction is conducted painlessly via vacuum-assisted mechanical lancet devices (TASSO+), minimizing tissue injury interference. Micro-volumes are centrifuged to isolate plasma. High-throughput electrochemiluminescence multiplex immunoassays (MSD QuickPlex SQ 120MM system) are deployed for highly sensitive, simultaneous quantification of pro- and anti-inflammatory cytokines, chemokines, metabolic hormones, and muscular destruction proteins.
• Oxidative Status Assessment: Spectrophotometric and fluorometric microplate assays quantify enzymatic antioxidant actions (superoxide dismutase, catalase, and reduced glutathione) alongside systemic lipid peroxidation and DNA degradation markers.
• Plasma Metabolomics: High-resolution liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q/TOF MS) is carried out to track Phase II phenolic metabolites. This fingerprinting links individual bioaccessibility and compound-conjugation variations directly to systemic inflammatory and oxidative recovery profiles.