Off-odors produced by volatile compounds remain a major barrier to consumer acceptance of plant-based proteins. This study presents a novel two-stage fermentation strategy to effectively reduce undesirable volatiles in eight plant proteins. A sequential fermentation process was developed using Lactobacillus plantarum in Stage 1 and a traditional yogurt culture, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. Bulgaricus and Lactobacillus acidophilus, in Stage 2. This method was applied to solutions of 9% soy, pea, chickpea, mung bean, faba bean, rice, barley-rice, and hemp proteins. Volatile profiles were analyzed via Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) and sensory evaluation before and after fermentation. The two-stage fermentation resulted in significant deodorization, with 95–99% reduction in key odorants such as hexanal, 2-pentylfuran, methoxypyrazines, and sulfur compounds across all proteins. The sequential approach significantly outperformed a one-stage fermentation. Allulose enhanced L. plantarum activity while strawberry preserves supported traditional yogurt culture performance. Non-fermentable additives such as pectin, xanthan gum, and oil had minimal effects on volatiles. The proposed fermentation method offers an effective, scalable, and clean-label solution for mitigating off-odors in plant-based proteins. By leveraging microbial metabolism and formulation synergies, this strategy provides a foundation for developing more palatable plant-based dairy alternatives.

This study examined the effects of rearing, physiological, and processing conditions on the volatile profile of Atlantic salmon. Fish were reared under two different temperature and light conditions, and three harvests were conducted at different time points for male and female fish. Fish were processed to yield fillets with or without skin. Volatiles were analyzed using SIFT-MS headspace analysis. Atlantic salmon reared in cooler temperatures under a 12 h light/dark cycle exhibited significantly lower concentrations of off-odor volatiles compared to those reared in warm conditions under continuous light, suggesting that cooler temperatures with a dark cycle help maintain freshness. A temperature shift from cool to warm further increased volatile accumulation. Longer rearing time resulted in higher volatile concentrations, attributed to greater biochemical products, increased susceptibility to lipid oxidation, protein degradation, and contaminant accumulation from the rearing environment. Males had higher volatile levels at 202 days, while females surpassed males by 242 days, likely due to increased biochemical accumulation associated with reproductive development. Fillets with skin exhibited significantly higher concentration of off-odor volatiles. These findings highlight the role of all studied factors in establishing optimum conditions to minimize spoilage-related volatiles and preserve the freshness of Atlantic salmon, with rearing temperature being the most critical factor.

Atlantic salmon (Salmo salar) is an important dietary source of health-promoting long-chain polyunsaturated fatty acids (PUFAs). As rearing conditions significantly influence fillet quality, this study evaluated the effects of warm and cool rearing temperature and photoperiod regimes on salmon growth, lipid profiles, and antioxidant capacity. Atlantic salmon (210 days old) were reared for 92 days under low temperature (14 °C, 12 h light) or high temperature (21 °C, 24 h light) conditions to simulate relevant seasonal conditions, winter and summer respectively. At day 302, conditions were reversed to create low-to-high (L→H) and high-to-low (H→L) treatments, continuing until day 362. Growth parameters, muscle lipid content, fatty acid profile, and antioxidant activity were measured at 302 and 362 days. Lipid content and fatty acid profile were also measured based on fillet location and fish sex. High rearing temperatures accelerated weight gain and increased total and neutral lipid contents, but elevated saturated fatty acids (SFA) and decreased PUFAs in structural polar lipids. High temperatures also significantly increased antioxidant activity, indicating elevated oxidative stress. Conversely, low temperatures suppressed growth but preserved essential PUFAs and maintained oxidative stability. Following the temperature shift, the H→L group had enriched polar lipids with PUFAs and maintained oxidative stability. On the other hand, L→H group showed lower PUFAs accumulation in polar lipid and enhanced oxidative stress. Total lipid content was higher in the head region, followed by the middle and tail sections of the fillet. However, fatty acid composition remained largely uniform across all three sections of the fillet. There were no significant differences in total lipid content between fish sexes. In conclusion, production efficiency and nutritional quality can be optimized by initially rearing salmon at high temperatures to promote rapid growth, followed by low temperature finishing phase to increase essential PUFA content and maintain oxidative stability.

Garlic contains sulfur volatiles that cause a bad odor after consumption. The objective of this study was to understand how yogurt and its components cause deodorization. Raw and fried garlic samples were mixed with various treatments and measurements of volatiles were conducted using a selected-ion flow-tube mass spectrometer. Frying garlic significantly reduced almost all sulfur volatile compounds. Raw garlic was deodorized more than fried garlic by all of the treatments. Fat, protein and water significantly reduced the concentration of sulfur-based volatiles in garlic. At the same concentration, either fat or protein produced higher deodorization, depending on the hydrophobicity of the volatile. Whey protein, casein and their complex all caused deodorization. Increasing the pH to 7 or heating changed the structure of the proteins and decreased the deodorization of the volatiles, showing the importance of proteins for deodorization. As the quantity of fat increased, the deodorization of the volatiles also increased. Foods with higher fat or protein content can be formulated to offer a potential solution to reduce the unpleasant odor associated with garlic consumption.

Consumption of garlic leads to the persistence of “garlic breath” due to the presence of malodorous sulfur volatiles which may persist for as long as 24 h. Therefore, the purpose of this study is to investigate the effect of yogurt and its components on the deodorization of garlic sulfur volatiles in breath and study the roles of these components in deodorization. Raw garlic was consumed with different treatments and at different times for breath analysis. Different components were mixed with the garlic for headspace analysis. Volatiles were measured using selected-ion flow-tube mass spectrometry. Consuming yogurt at the same time as garlic was more effective than consuming it before or after. Yogurt was the most effective at deodorization, followed by the emulsion, then protein or fat alone. Decreasing the pH of protein solutions increased deodorization because changes to the structure of the proteins exposed more binding sites for the volatiles, while decreasing the pH of water or fat had no effect on deodorization. Whey protein deodorized better than casein due to the presence of more cysteine binding sites for volatiles. This study proposes that the fat, protein, microbial culture, and water in yogurt have synergistic effects on the deodorization of garlic volatiles. This study’s findings can help in the development of novel products targeting sulfur volatiles, with broad applications for mitigating malodors produced by garlic.

Atlantic salmon (Salmo salar) is highly perishable during refrigerated storage due to the formation of off-odor volatile compounds that limit shelf life and consumer acceptance. This study investigated the development of off-odor volatiles in Atlantic salmon fillets during refrigerated storage and evaluated how rearing conditions influence storage-induced volatile formation. Salmon reared under warm (20.3 ± 1.95 °C with continuous light) or cool (13.1 ± 0.85 °C with a 12 h light–12 h dark cycle) conditions were harvested, stored at 4 ± 1 °C, and analyzed at 0, 3, 7, 9, and 15 days using selected-ion flow-tube mass spectrometry (SIFT-MS). Refrigerated storage was the primary driver of volatile formation, with lipid-derived aldehydes and alcohols forming early, followed by additional oxidation products as deterioration progressed, and finally, terminal oxidation products. These findings demonstrate distinct temporal pathways of off-odor volatile formation during refrigerated storage, linking early-stage oxidation of polar lipids, mid-stage involvement of neutral lipids, and late-stage accumulation of terminal and microbial products. Protein-derived volatiles exhibited compound-specific behavior, with reactive sulfur- and nitrogen-containing compounds increasing early or mid-storage and microbial metabolites accumulating steadily over time. Environmentally derived off-odor compounds, including geosmin and 2-methylisoborneol, were progressively released during storage as lipid structures degraded. Warm-reared salmon consistently exhibited higher concentrations of lipid- and protein-derived volatiles, indicating greater oxidative and proteolytic susceptibility. Rearing conditions modulate the extent but not the progression of these spoilage mechanisms. This mechanistic understanding provides a basis for targeted strategies to control off-odor volatile compound development and improve refrigerated shelf life and sensory quality of Atlantic salmon.