بهینه‌سازی فرآیند تولید سس هوادهی شده کم‌چرب به روش سطح پاسخ و ارزیابی ویژگی‌های فیزیکوشیمیایی و حسی آن

در این مطالعه روش جدید آماده سازی امولسیون‌های هوا در روغن (کف‌های روغنی) به‌منظور جایگزینی قطره‌های چربی با حباب‌های هوا ارائه شده، اثر غلظت سورفکتانت، سرعت و زمان هوادهی بر میزان تولید و پایداری کف‌ها بررسی شد. شرایط بهینه تولید (هوادهی مخلوط 10 درصد وزنی سورفکتانت با سرعت 3400 دور در دقیقه به مدت 15 دقیقه) با روش سطح پاسخ تعیین و کف‌ها برای تولید سس هوادهی شده آماده شدند. لینولئیک اسید به‌عنوان محرک مزه چربی (صفر و 3 میلی مولار) به سس‌ها اضافه و ویژگی‌های فیزیکوشیمیایی و حسی آن‌ها با سس‌های تجاری مقایسه شد. اسیدیته و ph نمونه‌ها در محدوده استاندارد قرار داشتند. بیشترین میزان ph مربوط به سس تجاری پرچرب بود (p<0.0001). سس تجاری بدون چربی با کم‌ترین میزان ph، اختلاف معنی‌داری با بقیه نداشت (p>0.05). بین ph سس‌های هوادهی شده (شاهد و حاوی لینولئیک اسید) اختلافی مشاهده نشد. اگرچه با گذشت زمان ph این سس‌ها کمی کاهش یافت، اما این تغییر معنی‌دار نبود (p>0.05). اعداد پراکسید و مقادیر مالون دی آلدهید نمونه‌های هوادهی شده و تجاری کم‌چرب در مدت هفت روز اختلافی با یکدیگر نداشتند (p>0.05). به‌طورکلی، روند اکسیداسیون سس پرچرب بسیار سریع‌تر از سایر نمونه‌ها بود. ظاهر، طعم و ویژگی‌های بافتی و پذیرش کلی محصولات هوادهی شده و نمونه‌های تجاری ارزیابی شد. پذیرش کلی سس هوادهی شده شاهد با سس حاوی لینولئیک اسید اختلاف قابل توجهی داشت (p <0.001)، اما پذیرش کلی نمونه حاوی لینولئیک اسید با سس‌های تجاری کم‌چرب و پرچرب معنی‌دار نبود (p>0.05). بر اساس این نتایج جایگزینی حباب‌های هوا و نیز افزودن محرک مزه چربی در چارچوب برنامه‌های کاهش چربی، می‌تواند تغییرات حسی موثر بر پذیرش مصرف‌کنندگان را به حداقل برساند.

Optimization of reduced-fat aerated sauce production process by response surface methodology and evaluation of its physicochemical and sensory properties

Introduction: Increasing dietlinked diseases and following that the consumers ongoing desire for healthier foods makes reducedfat products of outstanding importance in the food industry. This study aims to reduce the fat content of sauces as a traditional condiment through the incorporation of air bubbles in the oil phase. Response surface methodology (RSM) was used for identifying the effect of aeration process variables on foam properties. However, the main challenge of reducedfat foods is to ensure their acceptability. Recently fat taste has been introduced as a sixth basic taste. Fatty acids have been considered as the stimulus for this taste. So, linoleic acid as the stimulus for fat perception was added to the formulation to develop a product that tastes almost like fullfat versions but contains less fat. The advantages of aerated foods over conventional products are clear. Nonetheless, the determination of quality and sensory parameters during storage, marketing, and consuming is necessary. For this purpose, produced aerated sauces, along with commercial full and reducedfat sauces, were compared by measuring the acidity, pH, oxidative stability, and sensory properties. Materials and Methods: Required amounts of mono and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were generated by whipping the MDGoil mixtures. In the optimization study, the effect of MDG concentrations (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) was analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reducedfat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For the purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero, low, and fullfat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties. Results and Discussion: According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3400 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and fullfat commercial sauces, respectively. There was no difference (p>0.05) between the pH of the control and the linoleic acid containing aerated, as well as lowfat sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making the products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the fullfat one (p<0.05). Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the fullfat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance.  Conclusions: In this study, nonaqueous foam as a new approach for fat replacement in emulsionbased foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the fullfat sauce. Therefore, it seems that nonaqueous foam could be used successfully to develop reducedfat alternative foods, which could also be meet the consumers’ and marketing requirements.Materials and Methods: Required amounts of mono and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were obtained by whipping the MDGoil mixtures. In the optimization study, the effect of MDG concentration (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) were analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reducedfat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero and fullfat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties. Results and Discussion: According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3200 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and fullfat commercial sauces, respectively. There was no difference between the pH of the control and the linoleic acid containing aerated sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making them products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the commercial ones. Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the fullfat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance. Conclusions: In this study, nonaqueous foam as a new approach for fat replacement in emulsionbased foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the fullfat sauce. Therefore, it seems that nonaqueous foam could be used successfully to create reducedfat alternative foods, which could also be meet consumers’ and marketing requirements.