Lately, the essential oils industry has been one of the most expanding markets globally. However, the byproducts generated after the distillation of aromatic plants and their transformation to novel high-added value products consist of a major up-to-date challenge. Thus, the scope of the current study is the optimization of ultrasound-assisted extraction (UAE) for the recovery of phenolic compounds from rose (Rosa damascena) post-distillation side streams using Box–Behnken design. In particular, the highest total phenolic content (TPC) was achieved at 71% v/v ethanol–water solution, at 25 min, 40 mL/g dry sample and 53% ultrasound power, while ethanol content and extraction time were the most crucial factors (p-value ≤ 0.05) for UAE. Both solid (RSB) and liquid (LSB) rose side streams exhibited significant antiradical and antioxidant activities. The interpretation of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra confirmed the presence of compounds with properties such as phenolic compounds, phenolic amide derivatives, and alcohols in the extracts. Moreover, the flavonoids naringenin, quercetin, and kaempferol were the major phenolic compounds, identified in the extracts by liquid chromatography-tandem mass spectrometry analysis (LC-MS/MS), followed by gallic, protocatechuic, p-hydroxybenzoic, and rosmarinic acids. Furthermore, the LC-MS/MS results pinpointed the effect of factors other than the extraction conditions (harvesting parameters, climatic conditions, plant growth stage, etc.) on the phenolic fingerprint of RSB extracts. Therefore, RSB extracts emerge as a promising alternative antioxidant agent in food products.

Button mushrooms (Agaricus bisporus), one of the most common edible mushroom species, are sensitive to damages because of the absence of a protective skin layer and have a limited shelf life. Osmotic dehydration (OD), mainly used as a pre-processing step of conventional preservation methods, has been proposed as an efficient, mild treatment to preserve mushroom superior quality. In this study, response surface methodology, coupled with a Box–Behnken design, was used to investigate the effect of glycerol concentration (30–50%), temperature (30–50 °C), and duration of osmosis (0–180 min) in order to optimize the process prior to a subsequent freezing step. For each response, including mass transfer and selected quality indices, a second-order polynomial model was developed, and all process factors were found to have a significant impact. Based on the desirability approach and pre-set criteria, optimum operating conditions were estimated, namely osmosis at 50 °C, for 120 min, with a 42% glycerol solution, and the corresponding validation experiments were performed. Based on the error estimated between experimental and predicted values, polynomial equations were found to adequately predict parameter values. Based on a shelf-life test under frozen storage, OD-treated samples retained better quality attributes compared to their untreated counterparts.

The objective of the present study was the evaluation of the effect of slurry ice, as an alternative cooling medium during harvesting and transportation, on the quality parameters (e.g., microbiological stability, sensory attributes, physicochemical changes) and shelf life of fish. The effect of seasonal variability of seawater temperature on fish preservation using the tested cooling media was also investigated. Gilthead sea bream (Sparus aurata) was slaughtered and transported in different mixtures of conventional flake ice and slurry ice for 24 h. Three mixtures of ice were tested as T: slaughtered in flake ice and transported in flake ice (control), TC: slaughtered in slurry ice and transported in flake ice, T50: slaughtered and transported in slurry ice 50%–flake ice 50%. Samples were subsequently stored isothermally at 0 °C for shelf-life evaluation. Three independent experiments were performed at three different periods, i.e., January, April, and September, referring to a sea water temperature range of 13.3–26.8 °C. Higher sea water temperatures at catching led to lower microbial growth rates and proteolytic enzyme activities and longer shelf life of refrigerated whole fish. The partial replacement of conventional flake ice with slurry ice improved the quality and extended the shelf life of fish at 0 °C by 2–7 days. The results of the study support that the use of slurry ice may enable better quality maintenance and significant shelf-life extension of whole gilthead sea bream.

Oyster mushroom (Pleurotus ostreatus) is the second most widely cultivated mushroom worldwide but has a short shelf-life due to its high moisture content. Osmodehydrofreezing, including a step of osmotic dehydration (OD) prior to freezing, can be applied to extend product shelf life and preserve its quality characteristics. In this study, the effect of glycerol concentration (30–50%), temperature (30–50 °C), and immersion time (20–190 min) on mass transfer properties (WL, SG, a_w, %moisture content, salt intake) and important quality indices (color and texture) was investigated. Experiments were conducted using a Box–Behnken Design with three factors at three levels, second order equations were used to describe all measured parameters (following the Response Surface Methodology principles), and preselected desirability functions were used to set the acceptability criteria for optimization. The optimized conditions were found to be 38.7 °C, 30% glycerol, and 130 min of immersion time. To maximize OD effect, an initial step was investigated, using the side streams of rose flowers distillation (ODR samples), aiming at enriching samples with bioactive compounds. Frozen OD and ODR samples demonstrated a significant improvement in color and texture retention, and suffered from a reduced drip loss after thawing, compared to their untreated counterparts.

Mushroom production and consumption are gaining increased interest due to their unique flavor and nutritional value. However, in the mushroom industry, large amounts of by-products are generated, which have a high negative environmental and economic impact. In this study, an osmotic dehydration process followed by hot-air-drying was applied to mushroom stems to produce dried mushrooms as the end product. The osmotic dehydration conditions (concentration of hypertonic solution, specifically, 10–30% maltodextrin and 20–40% oligofructose; a treatment time of 40–80 min; and a temperature range of 30–50 °C) were optimized using response surface methodology (RSM). The results showed that a four-factor three-level Box–Behnken experimental design was effectively implemented to evaluate the effect of the process parameters and identify the optimal osmotic dehydration conditions for producing osmotically dehydrated mushrooms. The main factor affecting mass transfer was the osmosis temperature, and the optimal conditions were found to be 38 °C, 40% oligofructose and 19.3% maltodextrin as the osmotic agents, and 80 min of immersion time. Moreover, the results showed that osmotic pretreatment, in the optimal conditions, significantly reduced the required drying time of the by-products compared to traditional hot-air-drying, especially at milder drying temperatures. Consequently, the required energy was also reduced by at least 40% at 50 °C.

Endogenously formed N-nitroso compounds (NOCs) from nitrite use in red meat have been recently linked to the risk of colorectal cancer. Therefore, replacing sodium nitrite (E250) with natural antimicrobials, such as bioactive compounds, is an issue of great industrial and scientific interest. In this research, such compounds were extracted from rose petal (Rosa damascena) and rosemary leaf (Rosmarinus officinalis L.) by-products of the essential oil industry and appropriately introduced in commercial cured meat products, as partial nitrite replacers. Shelf-life tests demonstrated an inhibitory effect of the rose extracts on microbial growth, obtaining similar or reduced growth rates and a prolonged lag phase, when compared to conventionally produced samples (CNT): μ_max,ref = 0.128 vs. 0.166 d⁻¹ and λ_ref = 15.9 vs. 12.4 d at 4 °C, respectively. None of the bacon samples suffered from lipid oxidation in the examined period. The RSE samples (containing the rose extract and half of the nitrites) exhibited a good retention of their red color, receiving an acceptable sensory score throughout storage. Since the proposed partial nitrite replacement leads to an important shelf-life extension, namely 78 d (RSE) vs. 60 d (CNT), our results provide preliminary proof of the potential use and valorization of such side streams as effective natural antimicrobial agents for cured meat products, in order to reduce the use of nitrites.