Impact of pickling and brining on the perceptual and nutritional characteristics of sea lettuce (Ulva fenestrata)

· Seaweed foods with unique sensory profiles and high consumer appeal were developed. · Brining and pickling enhanced sensory profiles and reduced potential toxic elements. · All treatments reduced bitterness and fishy off-flavors found in raw Ulva . · Correlation analysis provides chemical explanations for perceived aromas. · Treated Ulva emerges as a refined ingredient in modern gastronomy. Seaweed is a promising candidate as a healthy, tasty, and sustainable future food in Western cultures, but currently lacks gastronomic applications in these settings. Therefore, this study aimed to refine the green seaweed Ulva fenestrata into sustainable, nutritious, and appealing food products and evaluate its quality and consumer acceptance. Five products – rehydrated Ulva (control), brined (6% NaCl), pickled in acetic acid, and pickled in cold and warm apple cider vinegar – were developed and assessed for nutritional, safety, and sensory characteristics. The raw material contained all essential amino acids at levels qualifying it as a complete protein and was rich in essential minerals such as calcium, potassium, magnesium, sodium, and sulfur. Acid treatments using acetic acid and apple cider vinegar effectively reduced undesirable elements, including arsenic, cadmium, and iodine. While pickling decreased hardness and greenness, brining preserved these physical attributes. Aroma profiles determined by SPME-GC-MS (solid-phase microextraction followed by gas chromatography with mass spectrometry) varied significantly across treatments: control and brined samples were dominated by dimethyl sulfide and 2-aziridinylethyl-amine, whereas pickled samples exhibited complex profiles characterized by aldehydes and acetic acid, imparting fermented, pungent, and fruity notes. Sensory evaluation by quantitative descriptive analysis (QDA) with trained experts revealed that brining enhanced seaweed odors, umami, and saltiness, while vinegar pickling introduced sweetness and distinctive vinegar-related flavors. Most importantly, the intense bitterness and fishy flavors from dimethyl sulfide were reduced in all treatments, especially in pickled products. Consumer acceptance was high for pickled products, indicating strong potential for culinary applications.