Development and Evaluation of Goat Milk and Papaya-Based Face Wash for Skin Care Applications

Now-a-days there has been a growing global shift toward the use of natural and herbal-based cosmetics, which is driven by rising consumer awareness of the potential adverse effects of synthetic skincare ingredients on both skin health and the environment. Consumers are increasingly seeking formulations that not only cleanse effectively but also deliver nourishment and rejuvenation via bioactive compounds derived from natural sources. Among such promising approaches, milk-based and fruit enzyme-based formulations have significant attention for their multifunctional benefits and biocompatibility ^[1]. Goat milk is one such ingredient, traditionally it is used in skincare and now receiving renewed research interest. It is rich in proteins, essential fatty acids, vitamins (A, B6, B12, E) and notably lactic acid, a mild alpha hydroxy acid (AHA) ^[2]. Lactic acid aids in the removal of dead skin cells, thereby facilitating smoother and brighter skin surfaces. Furthermore, goat milk’s lipid profile closely resembles that of human skin, and its pH is similar to that of the skin’s acid mantle, which makes it particularly suitable for sensitive and dry skin types. For cortico-dermatological and cosmetic uses, goat milk has used to support wound healing, tissue regeneration, sebum regulation, hydration, barrier repair and anti-inflammatory effects although much of the evidence remains preliminary ^[3].  Another ingredient is Papaya (Carica papaya), which is widely used for its skin-brightening, anti-inflammatory and exfoliating properties. The enzyme papain helps in the breakdown of inactive keratin and dead skin cell build-up; thus, it enhances the skin texture and tone Papaya is also rich in antioxidant vitamins such as A and C, which protect against oxidative stress and support skin renewal. The combination of goat milk and papaya therefore offers a promising synergy: gentle exfoliation and nourishment together in a mild formulation ^[5]. Conventional face washes often rely heavily on synthetic surfactants and chemical additives, which may strip the skin of its natural oils, disrupt the acid mantle, irritate sensitive skin and potentially lead to long-term barrier damage ^[6]. In contrast, a goat-milk and papaya-based face wash presents a skin-friendly, sustainable alternative: one that is rooted in naturally derived bioactive and designed for cleansing while maintaining skin health. Accordingly, the objective of this study is to formulate and evaluate a face wash incorporating goat milk and papaya extracts, with a focus on its physicochemical properties (pH, viscosity, foaming and spreadability), stability, cleansing efficacy and skin compatibility. The findings are intended to contribute to the growing field of natural cosmetic formulations and support the utilization of locally available bioactive raw materials in skincare product development ^[7].

MATERIALS AND METHODS

MATERIALS

Fresh goat milk was procured from a certified local dairy source. Ripe Carica papaya fruits were obtained from a local market and authenticated by the department of Pharmacognosy of Rupesh Badhan institute of pharmacy. The other excipients used in the formulation, sodium coccyl -iso-ethionate as a surfactant, turmeric powder as an anti-inflammatory and brightening agent, glycerin as a humectant, honey as a moisturizer and antibacterial, leucidal as a preservative and lavender oil for fragrance. All reagents and chemicals used were of analytical grade and procured from recognized suppliers ^[8].

Figure 3: Honey

Fresh papaya pulp was washed thoroughly, peeled, and homogenized using a laboratory blender. The pulp was air-dried at 45 °C till constant weight was achieved, after that it was pulverized into fine powder and extracted with 70% ethanol using a Soxhlet apparatus for 6 h. The extract was filtered and concentrated under reduced pressure using a rotary evaporator at 50 °C to obtain a semi-solid papaya extract. The extract was stored at 4 °C in an amber-colored container until further use ^[9].

Preparation of Goat Milk and Papaya Face Wash

The formulation was prepared by adopting the standard cold emulsification technique. The required quantity of goat milk was pasteurized and filtered to remove fat globules. In a beaker, the surfactant was mixed with distilled water under gentle stirring at 600 rpm. Glycerin, turmeric and honey were added to form uniform dispersion. Once the mixture attained homogeneity, the papaya extract and goat milk were incorporated gradually while maintaining continuous stirring to avoid phase separation. The fragrance and preservative were added at the final stage. The prepared face wash was stored in sterilized airtight containers at room temperature for further evaluation ^[10].

Table 1: Formula for Face Wash

Manufacturing Procedure

1. Blend goat milk and aloe vera gel gently.
2. Slowly add surfactant and glycerin; mix gently to avoid excessive foam.
3. Incorporate papaya pulp and turmeric powder evenly.
4. Add honey and essential oil.
5. Add preservative according to recommended dosage.
6. Fill in sanitized pump bottles or tubes.
7. Store refrigerated if fresh goat milk is used.

Figure 4: Formulated Face wash

Evaluation Of Physicochemical Parameters

1. pH Measurement

The pH of the face wash was determined using a calibrated digital pH meter. About 10 g of the formulation was dispersed in 100 ml of distilled water, and the reading was recorded at room temperature. The measurement was performed in triplicate.

2. Viscosity

Viscosity was measured using a Brookfield viscometer at 25 °C with spindle number 64 at 50 rpm. The results were expressed in centipoise (cp).

3. Foaming Capacity

Foaming ability was tested using the cylinder shake method. A 1% w/v solution of the face wash was prepared and transferred into a 250 ml graduated cylinder. The initial and final foam volumes were recorded after shaking for 10 s and allowing the foam to stand for 5 min. The foam stability index was calculated.

4. Spreadability

The spreadability of the formulation was determined by the slip-and-drag method. A known weight of sample was placed between two glass slides and compressed by a fixed weight. The time required for the upper slide to move a specified distance was recorded and spreadability was calculated.

5. Stability Study

The stability of the formulation was assessed under accelerated conditions (40 °C ± 2 °C / 75% ± 5% RH) for 30 days. Samples were evaluated at 0, 15, and 30 days for any change in color, odor, pH, or phase separation.

6. Microbial Load Test

Microbial contamination was examined by plate count method using nutrient agar for bacterial growth and Sabouraud dextrose agar for fungal growth. Plates were incubated at 37 °C and 25 °C, respectively, and colony-forming units (CFU/g) were counted after 48 h.

7. Sensory Evaluation

A small-scale user study was conducted with 20 healthy volunteers aged 21-40 years after obtaining informed consent. Participants evaluated the face wash for texture, fragrance, cleansing ability, and after-feel on a five-point hedonic scale (1 = poor to 5 = excellent). No adverse reactions were reported during the 8-days trial.

RESULTS AND DISCUSSION

Table 2: Comprehensive Evaluation of Goat Milk & Papaya Face Wash (n = 3)

1. Physicochemical Evaluation

The goat milk and papaya face wash formulation was evaluated for key physicochemical properties to assess its suitability for topical use. The results are summarized in Table 1.

Table 3: Physicochemical Properties of Goat Milk and Papaya Face Wash

Description

The measured pH of 6.1 is within the natural skin pH range, indicating minimal risk of irritation. Goat milk, rich in lactic acid, contributes to this mildly acidic pH, which is beneficial for maintaining the skin barrier.  The viscosity of 3100 cP ensures adequate retention on the skin without being runny, enhancing user experience. Moderate foaming (65%) is desirable in natural cleansers, as excessive foam is often associated with harsh synthetic surfactants. The spreadability value confirms that the formulation can be applied easily and evenly, enhancing cleansing efficiency

Figure 6: Foam of face wash

2. Stability Study

The accelerated stability study (40 °C / 75% RH) showed no phase separation, discoloration, or change in odor after 30 days. The pH remained stable (5.9–6.0), indicating that the goat milk and papaya extract-maintained formulation integrity. This confirms that natural ingredients can be effectively incorporated into a surfactant base without compromising stability.

3. Microbial Load

Microbial evaluation showed negligible bacterial and fungal growth (<10 CFU/g), well below the acceptable limits for cosmetic products (≤100 CFU/g). The addition of methylparaben and proper storage conditions ensured microbial safety, which is crucial for skin care formulations containing milk-based ingredients.

4. Sensory Evaluation

In the user study (n=20), the majority of participants rated the face wash as excellent in texture (82%), fragrance (77%), and cleansing ability (89%). No adverse reactions were reported, indicating good tolerability. The combination of goat milk and papaya extract provided a smooth, moisturizing effect with gentle exfoliation, confirming the synergistic benefit of these natural ingredients.

5. Stability Evaluation
   1. Temperature Stability

• Method: Store at 4°C, 25°C, 40°C; monitor 1 month for phase separation, odor, color.
• Purpose: Determines product robustness under different conditions.
• Expected Result: No separation, color, or odor changes
  2. Centrifugation Test

• Method: 3000 rpm for 10 min.
• Purpose: Evaluates emulsion stability.
• Expected Result: No separation or sedimentation
  3. Freeze-Thaw Cycles

• Method: Alternate between -5°C and 25°C, 3 cycles.
• Purpose: Tests stability against temperature fluctuations.
• Expected Result: Stable; no curdling or phase separation

6. Safety & Skin Compatibility
   1. 1. 1. 1. Patch Test / Skin Irritation

• Method: Apply 0.5 ml on the fore arm of healthy volunteers. observe 24–72 h for erythema, itching, rash.
• Purpose: Confirms safety for topical use.
• Expected Result: No irritation
  1. 1. 1. 2. After-feel

• Method: Organoleptic assessment after rinsing.
• Purpose: Evaluates moisturizing effect and consumer acceptability.
• Expected Result: Skin feels soft, hydrated, non-greasy

7. Fragrance Retention

• Method: Smell assessment 30 min after application.
• Purpose: Ensures consumer satisfaction and subtle fragrance persistence.
• Expected Result: Mild, pleasant residual scent

8. Stability & Shelf-Life Studies

Table 4: Stability & Shelf-Life Studies

Safety & Regulatory Compliance

• Skin Safety: Patch test recommended.
• Storage: Refrigerate if fresh milk used; avoid sunlight.
• Preservative: Use natural or cosmetic-approved preservatives.
• Compliance:
  • India: Drugs & Cosmetics Act 1940, Cosmetic Rules 2020
  • GMP: ISO 22716
  • Essential Oils: IFRA compliance

Claims & Labeling

Approved Claims:

• “Moisturizes and nourishes skin”
• “Gentle cleansing with natural ingredients”
• “Contains natural papaya enzyme for mild exfoliation”
• “Ayurvedic-inspired skincare”
• “Suitable for sensitive skin”

Cautions:

• Avoid contact with eyes; discontinue if irritation occurs.
• Refrigerate after opening (if using fresh goat milk).

Label Requirements:

• Product name, net quantity, ingredients, directions, storage, manufacturer info, batch number, manufacturing/expiry dates, Ayurvedic statement (“Ayurvedic-inspired formulation”).

Table 5: Testing Schedule