Researchers in Pakistan have fortified yogurt with microencapsulated sea buckthorn seed extract and reported that, in an alloxan-induced diabetic rat model, the highest dose tested lowered blood sugar to 87.72 mg/dL, a significant improvement compared with diabetic control animals. The study, published in Food Production, Processing and Nutrition, combined ultrasound-assisted extraction of sea buckthorn fruit seeds, encapsulation of the resulting extract in sodium alginate, incorporation of the microcapsules into yogurt, and a 21-day feeding trial in diabetic rats. The authors caution that the findings come from a small animal study and cannot be extrapolated directly to humans without well-designed clinical trials.
Sea buckthorn (Hippophae rhamnoides L.), a shrub of the family Elaeagnaceae, produces berries rich in vitamin C, vitamin E, vitamin K, carotenoids such as beta-carotene and beta-cryptoxanthin, flavonoids including quercetin and isorhamnetin, and essential fatty acids spanning omega-3, omega-6, omega-7 and omega-9. The team obtained the raw fruit from Skardu in Gilgit-Baltistan, Pakistan, harvested in October and stored at minus 18 degrees Celsius. Previous research cited by the authors has linked sea buckthorn bioactives to antioxidant, antidiabetic and hepatorenal protective activities, and to improved insulin resistance through regulation of the PI3K/AKT signaling pathway, although those mechanisms were not directly tested in the present work.
The instability of these compounds posed the central technical challenge. Vitamin C, carotenoids and polyphenols degrade readily when exposed to light, heat, oxygen and improper storage, which reduces antioxidant activity and therapeutic effectiveness. To address this, the researchers turned to ultrasound-assisted extraction, chosen because acoustic cavitation enhances mass transfer and raises extraction efficiency while preserving heat-sensitive constituents. Dried, powdered fruit seed material was combined with methanol and water in an 80:20 ratio, sonicated for a total of seven minutes with the temperature held below 35 degrees Celsius using pulse cycles of 55 seconds on and 60 seconds off, with the flask immersed in ice. After centrifugation, the methanol was removed on a rotary evaporator at 45 degrees Celsius and the dried extract was stored frozen for subsequent experiments.
Fourier transform infrared spectroscopy of the ultrasound-extracted sea buckthorn fruit seed extract, run across a wavelength range of 4000 to 500 inverse centimeters at 4 inverse centimeter resolution after 32 scans, revealed characteristic functional group stretches. A broad band at 3373 inverse centimeters corresponded to O-H stretching, commonly attributed to flavonoids and alcohols. A band at 2083 inverse centimeters indicated C-triple-bond-C stretching associated with unsaturated compounds such as alkynes, and a sharp peak at 1574 inverse centimeters was assigned to C=C or N-H bending in the amide II region, consistent with phenolic constituents and proteins. These spectral signatures confirmed the presence of bioactive compound classes in the extract before encapsulation.
Encapsulation proceeded by dissolving the sea buckthorn extract and a 2 percent sodium alginate solution together at a 1:10 weight ratio at 50 degrees Celsius, homogenizing the mixture, adjusting the pH to 3.75, and extruding it through a needle into a 2 molar calcium chloride gelling bath. The beads solidified for 30 minutes, were rinsed, freeze-dried and stored at 4 degrees Celsius. Sodium alginate, a widely used encapsulant that is generally recognized as safe, forms a protective matrix intended to prevent degradation of the bioactives and enable their release at the target site in the intestine. The authors note that using this material for targeted delivery of sea buckthorn nutraceuticals in diabetes management remains limited in the existing literature.
The fortified yogurt was prepared from pasteurized low-fat skim milk inoculated with Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, incubated for 15 hours at 37 degrees Celsius and stored at 5 degrees Celsius. Five formulations were produced: a control without extract, and treatments containing 50, 100, 150 and 200 grams per kilogram of SBFSE-loaded microcapsules, designated S1 through S4. All nutritional measures declined gradually over 21 days of refrigerated storage.
Sensory evaluation told a different story about the optimal dose. Twelve untrained panelists, four women and eight men, who were regular plain yogurt consumers rated the products on a 10-point hedonic scale at 0, 7, 14 and 21 days of storage. The lowest fortification level, S1 at 50 grams per kilogram, scored highest on the first day for color at 8.67, taste at 8.50, texture at 8.57, aroma at 8.82 and overall acceptance at 8.70. Scores for all treatments declined over storage, with substantial decreases by day 21, and the highest fortification level, S4, received the lowest ratings, including a texture score of 3.63 on the final day. The authors describe the panel as small and untrained, providing preliminary information on consumer acceptability rather than comprehensive sensory profiling.
The in vivo phase involved 42 male albino Wistar rats weighing 120 to 150 grams, allocated to six groups of seven animals each. Diabetes was induced by intraperitoneal injection of alloxan at 150 mg/kg, after which animals with blood glucose above 200 mg/dL were selected. Groups received either normal saline or SBFSE-fortified yogurt by oral gavage for 21 days at doses of 500, 600, 700 or 800 mg/kg body weight, expressed as active extract equivalent rather than total yogurt mass. The highest dose, A5 at 800 mg/kg, produced the greatest reduction in blood sugar to 87.72 mg/dL, significantly different from the diabetic positive control. Intermediate doses of 500, 600 and 700 mg/kg yielded glucose values of 97.38, 93.88 and 95.34 mg/dL respectively. The relationship between dose and glucose response was not strictly linear across the tested range.
Beyond glycemia, the fortified yogurt was associated with significant improvements in liver and kidney markers, including creatinine, potassium, sodium, urea, ALP, ALT and bilirubin, while AST showed no significant change, and in serum proteins including total protein, albumin, globulin and the albumin-globulin ratio, with the maximum effects again observed at the highest dose. Hematological parameters including white blood cells, basophils, eosinophils, monocytes, neutrophils, red blood cells, hemoglobin, hematocrit, MCH and MCHC were significantly affected, with lymphocytes the only measured parameter showing no significant difference. Lipid profile measures of total cholesterol, triglycerides, LDL, VLDL and HDL also changed significantly, with HDL increasing against the diabetic control. Histopathological examination of liver tissue showed that the diabetic control group exhibited fatty degeneration, inflammatory infiltration and vascular congestion, while the highest-dose group displayed hepatic architecture closely resembling the non-diabetic negative control, and the authors report that the treatments did not induce histological toxicity.
The study carries several limitations that the authors state explicitly. Sensory evaluation relied on a small panel of untrained participants, characterization of the microcapsules themselves, including encapsulation efficiency, particle size distribution, morphology, in vitro release behavior and long-term storage stability, was beyond the scope of the work, and the biological findings derive from an alloxan-induced diabetic rat model rather than human subjects. The authors call for detailed microcapsule characterization, larger and more representative sensory panels and well-designed clinical trials to validate the formulation’s efficacy and applicability. They also note that further research is needed to quantify the derivatives of the bioactive compounds that exert the functional impact. Within those boundaries, the work demonstrates that microencapsulation can preserve sea buckthorn bioactives through yogurt processing and storage, and that the resulting fortified product produced measurable biochemical changes in a rodent model of diabetes.
Subject of Research: Microencapsulated sea buckthorn seed extract fortified yogurt and its effects in an alloxan-induced diabetic rat model
Article Title: Ultrasound-extracted sea buckthorn in microencapsulated yogurt: a functional approach to diabetes management
Article References: Javaid, N., Amjad, A., Ismail, A., Shah, M., Zafar, S., Ahmad, S., Hussain, M., Chaudhary, M. N., & Abdi, G. (2026). Ultrasound-extracted sea buckthorn in microencapsulated yogurt: a functional approach to diabetes management. Food Production, Processing and Nutrition, 8(1), Article 77. https://doi.org/10.1186/s43014-026-00433-5
Image Credits: AI Generated
DOI: 10.1186/s43014-026-00433-5
Keywords: sea buckthorn, microencapsulation, sodium alginate, functional yogurt, diabetic rats, blood glucose, antioxidant activity, ultrasound-assisted extraction, FTIR spectroscopy, bioactive compounds, liver function, lipid profile
News Source: Alan Morgan. (October 28, 2026). Microencapsulated Sea Buckthorn Yogurt Lowered Blood Sugar in Diabetic Rats, Study Reports. Scienmag.
