Functionalization of Pasteurized Milk Using Rosemary, Thyme, and Ammoides Aqueous Extracts for Better Microbial Quality and an Improved Antioxidant Activity

Abstract

This study aimed to evaluate the effects of thyme (Thymus vulgaris L.), rosemary (Rosmarinus officinalis L.), and ammoides (Ammoidespusilla L.) aqueous extracts supplementation on the quality of heat-treated (55, 65, and 75 °C) raw milk (sample lots: A, B, and C) and cold-stored pasteurized milk (lot D). The three herbs have shown rich polyphenol contents (32.65–104.23 mgGAE/g), relevant antioxidant capacity, and high caffeic and rosmarinic acids and catechin contents. A significant reduction in psychrotrophic and total viable bacteria counts (PC and TVC) was attained following milk extract supplementation in both experiments. Monitoring PC and TVC counts in sample lots (A, B, and C) has revealed a significant improvement in extracts’ effectiveness in reducing the TVC count with the increment of temperature. The highest reductions of PC and TVC counts were achieved, respectively, in samples treated with thyme and rosemary in (lots: A, B, and C) and in samples treated with ammoides and thyme in (lot D). Thyme extract showed the highest milk serum DPPH scavenging activity (74.84% at 0.1 mg/mL) and induced a significant Listeria monocytogenes growth inhibition (>1 Log cycle). The sensory evaluation of supplemented milk has shown good consumer acceptability of ammoides-supplemented milk, quite similar to the control sample.

Rosemary: Unrevealing an old aromatic crop as a new source of promising functional food additive—A review

“…The nonvolatile rosemary extracts have been proven to contain abundant polyphenols, diterpenes, triterpene acids, and other substances with biologically fascinating anti‐inflammatory, antibacterial, antioxidant, antispasmodic, diuretic, and other pharmacological properties (Jalloul et al., 2022). Rosemary is especially known for its potent antioxidant properties, which make rosemary the most promising natural food antioxidant in the near future; it is replacing the chemical antioxidants in the food industry because it is absolutely safe and readily commercially available.…”

“…Worldwide, the food requirement of people in modern society has gradually transformed from basic survival needs to functional developments, such as adding flavors, prolonging shelf life, improving dietary profile, and relieving diet‐related chronic diseases (Jalloul et al., 2022). Natural compounds have always served as important functional additive sources for the food industry.…”

“…The total phenolic content of fresh rosemary extract was about 32.65 mg gallic acid equivalent/g of extract (mg GAE/g Ext). Among phenol content, the flavonoid content of rosemary extract was 14.56 mg catechin equivalent/g of extract (mg CE/g Ext), reaching about 50% of the total phenolic compounds (Jalloul et al., 2022). Another study showed that the total phenolic content in dry rosemary extract was about 95.8 mg gallic acid equivalent/g of extract (mg CE/g Ext), and this study also disclosed that the total phenolic compounds could be significantly affected by the extraction method, plant harvest period, climate, and other environmental conditions (Lamponi et al., 2021).…”

“…The main common polyphenols in the aqueous extracts of rosemary were catechin hydrate, ferulic acid, rosmarinic acid, epicatechin‐3‐ O ‐gallate, caffeic acid, sinapic acid, chlorogenic acid, p‐ coumaric acid, isoquercitrin, resorcinol, and isorhamnetin‐3‐ O ‐glucoside (Jalloul et al., 2022; Ozarowski et al., 2013; Sharma et al., 2020). Among these, ferulic acid and rosmarinic acid were two of the most main phenolic acids of rosemary with concentrations up to 97.53 and 74.64 mg/100 g of extract, respectively (Charpentier et al., 2022).…”

“…In modern society, natural products are believed to be beneficial to health and relatively safe and they can avoid side effects unlike their chemosynthetic counterparts. As a result, food antioxidants have shifted preferences from synthetic compounds to natural sources (Jalloul et al., 2022), making rosemary increasingly important in the modern food industry.…”